EPA/625/R-96/01 Ob
Compendium of Methods
for the Determination of Toxic
Organic Compounds
in Ambient Air
Second Edition
Compendium Method TO-14A
Determination Of Volatile Organic
Compounds (VOCs) In Ambient Air Using
Specially Prepared Canisters With
Subsequent Analysis By Gas
Chromatography
Center for Environmental Research Information
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
January 1999
-------
Method TO-14A
Acknowledgements
This Method was prepared for publication in the Compendium of Methods for the Determination of Toxic
Organic Compounds in Ambient Air, Second Edition, (EPA/625/R-96/010b), which was prepared under
Contract No. 68-C3-0315, WA No. 3-10, by Midwest Research Institute (MRI), as a subcontractor to Eastern
Research Group, Inc. (ERG), and under the sponsorship of the U.S. Environmental Protection Agency (EPA).
Justice A. Manning, John O. Burckle, and Scott Hedges, Center for Environmental Research Information (CERI),
and Frank F. McElroy, National Exposure Research Laboratory (NERL), all in the EPA Office of Research and
Development, were responsible for overseeing the preparation of this method. Additional support was provided
by other members of the Compendia Workgroup, which include:
• John O. Burckle, U.S. EPA, ORD, Cincinnati, OH
James L. Cheney, Corps of Engineers, Omaha, NB
Michael Davis, U.S. EPA, Region 7, KC, KS
• Joseph B. Elkins Jr., U.S. EPA, OAQPS, RTP, NC
Robert G. Lewis, U.S. EPA, NERL, RTP, NC
Justice A. Manning, U.S. EPA, ORD, Cincinnati, OH
• William A. McClenny, U.S. EPA, NERL, RTP, NC
Frank F. McElroy, U.S. EPA, NERL, RTP, NC
• Heidi Schultz, ERG, Lexington, MA
William T. "Jerry" Winberry, Jr., EnviroTech Solutions, Cary, NC
Method TO-14 was originally published in March of 1989 as one of a series of peer reviewed methods in the
second supplement to "Compendium of Methods for the Determination of Toxic Organic Compounds in
Ambient Air," EPA 600/4-89-018. Method TO-14 has been revised and updated as Method TO-14A in this
Compendium to eliminate time sensitivity material and correct a small number of errors.
Peer Reviewer
• Lauren Drees, U.S. EPA, NRMRL, Cincinnati, OH
Finally, recognition is given to Frances Beyer, Lynn Kaufman, Debbie Bond, Cathy Whitaker, and Kathy Johnson
of Midwest Research Institute's Administrative Services staff whose dedication and persistence during the
development of this manuscript has enabled it's production.
DISCLAIMER
This Compendium has been subjected to the Agency's peer and administrative review, and it has been
approved for publication as an EPA document. Mention of trade names or commercial products does
not constitute endorsement or recommendation for use.
n
-------
METHOD TO-14A
Determination Of Volatile Organic Compounds (VOCs) In Ambient Air Using Specially
Prepared Canisters With Subsequent Analysis By Gas Chromatography
TABLE OF CONTENTS
Page
1. Scope 14A-1
2. Summary of Method 14A-1
3. Significance 14A-4
4. Applicable Documents 14A-5
4.1 ASTM Standards 14A-5
4.2 EPA Documents 14A-5
4.3 Other Documents 14A-6
5. Definitions 14A-6
6. Interferences and Limitations 14A-7
7. Apparatus 14A-7
7.1 Sample Collection 14A-7
7.2 Sample Analysis 14A-9
7.3 Canister Cleaning System 14A-11
7.4 Calibration System and Manifold 14A-11
8. Reagents and Materials 14A-11
8.1 Gas Cylinders of Helium, Hydrogen, Nitrogen, and Zero Air 14A-11
8.2 Gas Calibration Standards 14A-11
8.3 Cryogen 14A-12
8.4 Gas Purifiers 14A-12
8.5 Deionized Water 14A-12
8.6 4-Bromofluorobenzene 14A-12
8.7 Hexane 14A-12
8.8 Methanol 14A-12
9. Sampling System 14A-12
9.1 System Description 14A-12
9.1.1 Subatmospheric Pressure Sampling 14A-12
9.1.2 Pressurized Sampling 14A-13
9.1.3 All Samplers 14A-13
9.2 Sampling Procedure 14A-14
in
-------
TABLE OF CONTENTS (continued)
Page
10. Analytical System 14A-15
10.1 System Description 14A-16
10.2 GC/MS/SCAN/SIM System Performance Criteria 14A-19
10.3 GC/FID/ECD System Performance Criteria (With Optional PID System) 14A-20
10.4 Analytical Procedures 14A-22
11. Cleaning and Certification Program 14A-25
11.1 Canister Cleaning and Certification 14A-25
11.2 Sampling System Cleaning and Certification 14A-26
12. Performance Criteria and Quality Assurance 14A-27
12.1 Standard Operating Procedures (SOPs) 14A-27
12.2 Method Relative Accuracy and Linearity 14A-27
12.3 Method Modification 14A-28
12.4 Method Safety 14A-29
12.5 Quality Assurance 14A-29
13. Acknowledgements 14A-30
14. References 14A-32
APPENDIX A. Availability of VOC Standards From U. S. Environmental Protection Agency (USEPA)
APPENDIX B. Operating Procedures for a Portable Gas Chromatograph Equipped with a
Photoionization Detector
APPENDIX C. Installation and Operating Procedures for Alternative Air Toxics Samplers
IV
-------
METHOD TO-14A
Determination Of Volatile Organic Compounds (VOCs) In Ambient Air Using Specially
Prepared Canisters With Subsequent Analysis By Gas Chromatography
1. Scope
1.1 This document describes a procedure for sampling and analysis of volatile organic compounds (VOCs) in
ambient air. The method was originally based on collection of whole air samples in SUMMA® passivated
stainless steel canisters, but has now been generalized to other specially prepared canisters (see Section 7.1.1.2).
The VOCs are separated by gas chromatography and measured by a mass spectrometer or by multidetector
techniques. This method presents procedures for sampling into canisters to final pressures both above and below
atmospheric pressure (respectively referred to as pressurized and subatmospheric pressure sampling).
1.2 This method is applicable to specific VOCs that have been tested and determined to be stable when stored
in pressurized and sub-atmospheric pressure canisters. Numerous compounds, many of which are chlorinated
VOCs, have been successfully tested for storage stability in pressurized canisters (1-3). However, minimal
documentation is currently available demonstrating stability of VOCs in subatmospheric pressure canisters.
1.3 The Compendium Method TO-14A target list is shown in Table 1. These compounds have been successfully
stored in canisters and measured at the parts per billion by volume (ppbv) level. This method applies under most
conditions encountered in sampling of ambient air into canisters. However, the composition of a gas mixture in
a canister, under unique or unusual conditions, will change so that the sample is known not to be a true
representation of the ambient air from which it was taken. For example, low humidity conditions in the sample
may lead to losses of certain VOCs on the canister walls, losses that would not happen if the humidity were
higher. If the canister is pressurized, then condensation of water from high humidity samples may cause
fractional losses of water-soluble compounds. Since the canister surface area is limited, all gases are in
competition for the available active sites. Hence an absolute storage stability cannot be assigned to a specific
gas. Fortunately, under conditions of normal usage for sampling ambient air, most VOCs can be recovered from
canisters near their original concentrations after storage times of up to thirty days.
2. Summary of Method
2.1 Both subatmospheric pressure and pressurized sampling modes typically use an initially evacuated canister
and pump-ventilated sample line during sample collection. Pressurized sampling requires an additional pump
to provide positive pressure to the sample canister. A sample of ambient air is drawn through a sampling train
comprised of components that regulate the rate and duration of sampling into a pre-evacuated specially prepared
passivated canister.
2.2 After the air sample is collected, the canister valve is closed, an identification tag is attached to the canister,
a chain-of-custody (COC) form completed, and the canister is transported to a predetermined laboratory for
analysis.
2.3 Upon receipt at the laboratory, the canister tag data is recorded, the COC completed, and the canister is
attached to the analytical system. During analysis, water vapor is reduced in the gas stream by a Nafion® dryer
(if applicable), and the VOCs are then concentrated by collection in a cryogenically-cooled trap. The cryogen
is then removed and the temperature of the trap is raised. The VOCs originally collected in the trap are
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-1
-------
Method TO-14A
VOCs
revolatilized, separated on a GC column, then detected by one or more detectors for identification and
quantitation.
2.4 The analytical strategy for Compendium Method TO-14A involves using a high-resolution gas
chromatograph (GC) coupled to one or more appropriate GC detectors. Historically, detectors for a GC have
been divided into two groups: non-specific detectors and specific detectors. The non-specific detectors include,
but are not limited to, the nitrogen-phosphorus detector (NPD), the flame ionization detector (FID), the electron
capture detector (ECD) and the photo-ionization detector (PID). The specific detectors include the linear
quadrupole mass spectrometer (MS) operating in either the select ion monitoring (SIM) mode or the SCAN mode,
or the ion trap detector (see Compendium Method TO-15). The use of these detectors or a combination of these
detectors as part of the analytical scheme is determined by the required specificity and sensitivity of the
application. While the non-specific detectors are less expensive per analysis and in some cases far more sensitive
than the specific detectors, they vary in specificity and sensitivity for a specific class of compounds. For
instance, if multiple halogenated compounds are targeted, an ECD is usually chosen; if only compounds
containing nitrogen or phosphorus are of interest, a NPD can be used; or, if a variety of hydrocarbon compounds
are sought, the broad response of the FID or PID is appropriate. In each of these cases, however, the specific
identification of the compound within the class is determined only by its retention time, which can be subject to
shifts or to interference from other non-targeted compounds. When misidentification occurs, the error is generally
a result of a cluttered chromatogram, making peak assignment difficult. In particular, the more volatile organics
(chloroethanes, ethyltoluenes, dichlorobenzenes, and various freons) exhibit less well defined chromatographic
peaks, leading to possible misidentification when using nonspecific detectors. Quantitative comparisons indicate
that the FID is more subject to error than the ECD because the ECD is a much more selective detector and
exhibits a stronger response. Identification errors, however, can be reduced by: (a) employing simultaneous
detection by different detectors or (b) correlating retention times from different GC columns for confirmation.
In either case, interferences on the non-specific detectors can still cause error in identifying compounds of a
complex sample. The non-specific detector system (GC/NPD/FID/ECD/PID), however, has been used for
approximate quantitation of relatively clean samples. The non-specific detector system can provide a "snapshot"
of the constituents in the sample, allowing determination of:
— Extent of misidentification due to overlapping peaks.
— Determination of whether VOCs are within or not within concentration range, thus requiring further
analysis by specific detectors (GC/MS/SCAN/SIM) (i.e., if too concentrated, the sample is further
diluted).
— Provide data as to the existence of unexpected peaks which require identification by specific detectors.
On the other hand, the use of specific detectors (MS coupled to a GC) allows positive compound identification,
thus lending itself to more specificity than the multidetector GC. Operating in the SIM mode, the MS can readily
approach the same sensitivity as the multidetector system, but its flexibility is limited. For SIM operation the
MS is programmed to acquire data for a limited number of targeted compounds. In the SCAN mode, however,
the MS becomes a universal detector, often detecting compounds which are not detected by the multidetector
approach. The GS/MS/SCAN will provide positive identification, while the GC/MS/SIM procedure provides
quantitation of a restricted list of VOCs, on a preselected target compound list (TCL).
If the MS is based upon a standard ion trap design, only a scanning mode is used (note however, that the Select
Ion Storage (SIS) mode of the ion trap has features of the SIM mode). See Compendium Method TO-15 for
further explanation and applicability of the ion-trap to the analysis of VOCs from specially prepared canisters.
Page 14A-2
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
The analyst often must decide whether to use specific or non-specific detectors by considering such factors as
project objectives, desired detection limits, equipment availability, cost and personnel capability in developing
an analytic strategy. A list of some of the advantages and disadvantages associated with non-specific and specific
detectors may assist the analyst in the decision-making process.
Non-specific Multidetector Analytical System
Advantages
• Somewhat lower equipment cost than GC/MS
• Less sample volume required for analysis
• More sensitive
- ECD may be 1000 times more sensitive than
GC/MS
• positive compound identification
• can identify all compounds
• less operator interpretation
• can resolve co-eluting peaks
Disadvantages
• Multiple detectors to calibrate
• Compound identification not positive
• Lengthy data interpretation (1 hour each for
analysis and data reduction)
• Interference(s) from co-eluting compound(s)
• Cannot identify unknown compounds
- outside range of calibration
- without standards
• Does not differentiate targeted compounds from
interfering compounds
• lower sensitivity than GC/MS/SIM
• greater sample volume required than for
multidetector GC
• somewhat greater equipment cost than
multidetector GC
Specific Detector Analytical System
GC/MS/SIM
Advantages
positive compound identification
greater sensitivity than GC/MS/SCAN
less operator interpretation than
multidetector GC
can resolve co-eluting peaks
more specific than the multidetector GC
Disadvantages
• cannot identify nonspecified compounds (ions)
• somewhat greater equipment cost than
for multidetector GC
• greater sample volume required than for
multidetector GC
• universality of detector sacrified to achieve
enhancement in sensitivity
GC/MS/SCAN
The analytical finish for the measurement chosen by the analyst should provide a definitive identification and a
precise quantitation of volatile organics. In a large part, the actual approach to these two objectives is subject
to equipment availability. Figure 1 indicates some of the favorite options that are used in Compendium
Method TO-14A. The GC/MS/SCAN option uses a capillary column GC coupled to a MS operated in a scanning
mode and supported by spectral library search routines. This option offers the nearest approximation to
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-3
-------
Method TO-14A
VOCs
unambiguous identification and covers a wide range of compounds as defined by the completeness of the spectral
library. GC/MS/SIM mode is limited to a set of target compounds which are user defined and is more sensitive
than GC/MS/SCAN by virtue of the longer dwell times at the restricted number of m/z values. Both these
techniques, but especially the GC/MS/SIM option, can use a supplemental general nonspecific detector to
verify/identify the presence of VOCs. Finally the option labelled GC-multidetector system uses a combination
of retention time and multiple general detector verification to identify compounds. However, interference due
to nearly identical retention times can affect system quantitation when using this option.
Due to low concentrations of toxic VOCs encountered in urban air (typically less than 25 ppbv and the majority
below 10 ppbv) along with their complicated chromatographs, Compendium Method TO-14A strongly
recommends the specific detectors (GC/MS/S CAN/SIM) for positive identification and for primary quantitation
to ensure that high-quality ambient data is acquired.
For the experienced analyst whose analytical system is limited to the non-specific detectors, Section 10.3 does
provide guidelines and example chromatograms showing typical retention times and calibration response factors,
and utilizing the nonspecific detectors (GC/FID/ECD/PID) analytical system as the primary quantitative
technique.
Compendium Method TO-15 is now available as a guidance document containing additional advice on the
monitoring of VOCs. Method TO-15 contains information on alternative water management systems, has a more
complete quality control section, shows performance criteria that any monitoring technique must achieve for
acceptance, and provides guidance specifically directed at compound identification by mass spectrometry.
3. Significance
3.1 The availability of reliable, accurate and precise monitoring methods for toxic VOCs is a primary need for
state and local agencies addressing daily monitoring requirements related to odor complaints, fugitive emissions,
and trend monitoring. VOCs enter the atmosphere from a variety of sources, including petroleum refineries,
synthetic organic chemical plants, natural gas processing plants, biogenic sources, and automobile exhaust. Many
of these VOCs are toxic so that their determination in ambient air is necessary to assess human health impacts.
3.2 The canister-based monitoring method for VOCs has proven to be a viable and widely used approach that
is based on research and evaluation performed since the early 1980s. This activity has involved the testing of
sample stability of VOCs in canisters and the design of time-integrative samplers, the development of procedures
for analysis of samples in canisters, including the procedure for VOC preconcentration from whole air, the
treatment of water vapor in the sample, and the selection of an appropriate analytical finish has been
accomplished. The canister-based method was initially summarized by EPA as Method TO-14 in the First
Supplement to the Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient
Air. The present document updates the original Compendium Method TO-14 with correction of time-sensitive
information and other minor changes as deemed appropriate.
3.3 The canister-based method is now a widely used alternative to the solid sorbent-based methods. The method
has sub-ppbv detection limits for samples of typically 300-500 mL of whole air and duplicate and replicate
precisions under 20 percent as determined in field tests. Audit bias values average within the range of
±10 percent. These performance parameters are generally adequate for monitoring at the 10"5 lifetime exposure
risk levels for many VOCs.
Page 14A-4
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
3.4 Collection of ambient air samples in canisters provides a number of advantages: (1) convenient integration
of ambient samples over a specific time period (e.g., 24 hours); (2) remote sampling and central analysis; (3) ease
of storing and shipping samples; (4) unattended sample collection; (5) analysis of samples from multiple sites
with one analytical system; (6) collection of sufficient sample volume to allow assessment of measurement
precision and/or analysis of samples by several analytical systems; and (7) storage stability for many VOCs over
periods of up to 30 days. To realize these advantages, care must be exercised in selection, cleaning, and handling
sample canisters and sampling apparatus to avoid losses or contamination.
3.5 Interior surfaces of canisters are treated by any of a number of passivation processes, one of which is
SUMMA polishing as identified in the original Compendium Method TO-14. Other specially prepared canisters
are also available (see Section 7.1.1.2).
3.6 The canister-based method for monitoring VOCs is the alternative to the solid sorbent-based method
described in conventional methods such as the Compendium Methods TO-1 and TO-2, and in the new
Compendium Method TO-17 that describes the use multisorbent packings including the use of new carbon-based
sorbents. It also is an alternative to on-site analysis in those cases where integrity of samples during storage and
transport has been established.
4. Applicable Documents
4.1 ASTM Standards
• Method D1356 Definition of Terms Relating to Atmospheric Sampling and Analysis
• Method E260 Recommended Practice for General Gas Chromatography
• Method E355 Practice for Gas Chromatography Terms and Relationships
• Method D31357 Practice for Planning and Sampling of Ambient Atmospheres
• Method D5466-93 Determination of Volatile Organic Chemicals in Atmospheres (Canister Sampling
Methodology)
4.2 EPA Documents
• Technical Assistance Document for Sampling and Analysis Toxic Organic Compounds in Ambient Air,
U. S. Environmental Protection Agency, EPA-600/4-83-027, June 1983.
• Quality Assurance Handbook for Air Pollution Measurement Systems, U. S. Environmental Protection
Agency, EPA-600/R-94-038b, May 1994.
• Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air: Method
TO-14, Second Supplement, U. S. Environmental Protection Agency, EPA 600/4-89-018, March 1989.
• Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air: Method
TO-15, Second Edition, U. S. Environmental Protection Agency, EPA 625/R-96-010b, January 1997.
• Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air, First
Supplement, U. S. Environmental Protection Agency, Research Triangle Park, NC, EPA-600/4-87-006,
September 1997.
• Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air: Method
TO-1, U. S. Environmental Protection Agency, Research Triangle Park, NC, EPA-600/4-84-041, 1986.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-5
-------
Method TO-14A
VOCs
4.3 Other Documents
• U. S. Environmental Protection Agency Technical Assistance Document (3).
• Laboratory and Ambient Air Studies (4-17).
5. Definitions
[Note: Definitions used in this document and any user-prepared Standard Operating Procedures (SOPSs)
should be consistent with those used in ASTM D1356. All abbreviations and symbols are defined within this
document at the point of first use.]
5.1 Absolute Canister Pressure (Pg+Pa)—gauge pressure in the canister (kPa, psi) and Pa = barometric
pressure (see Section 5.2).
5.2 Absolute Pressure—pressure measured with reference to absolute zero pressure (as opposed to atmospheric
pressure), usually expressed as kPa, mm Hg or psia.
5.3 Cryogen—a refrigerant used to obtain very low temperatures in the cryogenic trap of the analytical system.
A typical cryogen is liquid nitrogen (bp -195.8°C) or liquid argon (bp -185.7°C).
5.4 Dynamic Calibration—calibration of an analytical system using calibration gas standard concentrations
in a form identical or very similar to the samples to be analyzed and by introducing such standards into the inlet
of the sampling or analytical system in a manner very similar to the normal sampling or analytical process.
5.5 Gauge Pressure—pressure measured above ambient atmospheric pressure (as opposed to absolute
pressure). Zero gauge pressure is equal to ambient atmospheric (barometric) pressure.
5.6 MS/SCAN—the GC is coupled to a MS programmed in the SCAN mode to scan all ions repeatedly during
the GC run. As used in the current context, this procedure serves as a qualitative identification and
characterization of the sample.
5.7 MS/SIM—the GC is coupled to a MS programmed to acquire data for only specified ions and to disregard
all others. This is performed using SIM coupled to retention time discriminators. The GC/SIM analysis provides
quantitative results for selected constituents of the sample gas as programmed by the user.
5.8 Megabore® Column—chromatographic column having an internal diameter (I.D.) greater than 0.50-mm.
The Megabore® column is a trademark of the J&W Scientific Co. For purposes of this method, Megabore®
refers to chromatographic columns with 0.53-mm I.D.
5.9 Pressurized Sampling—collection of an air sample in a canister with a (final) canister pressure above
atmospheric pressure, using a sample pump.
5.10 Qualitative Accuracy—the ability of an analytical system to correctly identify compounds.
5.11 Quantitative Accuracy—the ability of an analytical system to correctly measure the concentration of an
identified compound.
Page 14A-6
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
5.12 Static Calibration—calibration of an analytical system using standards in a form different from the
samples to be analyzed. An example of a static calibration would be injecting a small volume of a high
concentration standard directly onto a GC column, bypassing the sample extraction and preconcentration portion
of the analytical system.
5.13 Subatmospheric Sampling—collection of an air sample in an evacuated canister at a (final) canister
pressure below atmospheric pressure, without the assistance of a sampling pump. The canister is filled as the
internal canister pressure increases to ambient or near ambient pressure. An auxiliary vacuum pump may be used
as part of the sampling system to flush the inlet tubing prior to or during sample collection.
6. Interferences and Limitations
6.1 Interferences can occur in sample analysis if moisture accumulates in the dryer (see Section 10.1.1.2). An
automated cleanup procedure that periodically heats the dryer to about 100°C while purging with zero air
eliminates any moisture buildup. This procedure does not degrade sample integrity for Compendium
Method TO-14A target compound list (TCL) but can affect some organic compounds.
6.2 Contamination may occur in the sampling system if canisters are not properly cleaned before use.
Additionally, all other sampling equipment (e.g., pump and flow controllers) should be thoroughly cleaned to
ensure that the filling apparatus will not contaminate samples. Instructions for cleaning the canisters and
certifying the field sampling system are described in Sections 11.1 and 11.2, respectively.
6.3 The Compendium Method TO-14A analytical system employs a Nafion® permeable membrane dryer to
remove water vapor from the sample stream. Polar organic compounds permeate this membrane in a manner
similar to water vapor and rearrangements can occur in some hydrocarbons due to the acid nature of the dryer.
Compendium Method TO-15 provides guidance associated with alternative water management systems
applicable to the analysis of a large group of VOCs in specially-treated canisters.
7. Apparatus
[Note: Equipment manufacturers identified in this section were originally published in Compendium
Method TO-14 as possible sources of equipment. They are repeated in Compendium Method TO-14A as
reference only. Other manufacturers' equipment should work as well, as long as the equipment is equivalent.
Modifications to these procedures may be necessary if using other manufacturers' equipment.]
7.1 Sample Collection
[Note: Subatmospheric pressure and pressurized canister sampling systems are commercially available and
have been used as part of U.S. Environmental Protection Agency's Toxic Air Monitoring Stations (TAMS),
Urban Air Toxic Monitoring Program (UATMP), the non-methane organic compound (NMOC) Sampling and
Analysis Program, and in the Photochemical Assessment Monitoring Stations (PAMS).]
7.1.1 Subatmospheric Pressure (see Figure 2 Without Metal Bellows Type Pump).
7.1.1.1 Sampling Inlet Line. Stainless steel tubing to connect the sampler to the sample inlet.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-7
-------
Method TO-14A
VOCs
7.1.1.2 Specially-Treated Sample Canister. Leak-free stainless steel pressure vessels of desired volume
(e.g., 6 L), with valve and passivated interior surfaces. Major manufacturers and re-suppliers are:
BRC/Ramussen
17010NW Skyline Blvd.
Portland, OR 97321
Meriter
1790 Potrero Drive
San Jose, CA 95124
Restec Corporation
110 Benner Circle
Bellefonte, PA 16823-8812
XonTech Inc.
6862 Hayenhurst Avenue
VanNuys, CA 91406
Scientific Instrumentation Specialists
P.O. Box 8941
Moscow, ID 83843
Graseby
500 Technology Ct.
Smyrna, GA 30832
7.1.1.3 Stainless Steel Vacuum/Pressure Gauge. Capable of measuring vacuum (-100 to 0 kPa or 0
to 30 in. Hg) and pressure (0-206 kPa or 0-30 psig) in the sampling system, Matheson, P.O. Box 136, Morrow,
GA 30200, Model 63-3704, or equivalent. Gauges should be tested clean and leak tight.
7.1.1.4 Electronic Mass Flow Controller. Capable of maintaining a constant flow rate (± 10%) over
a sampling period of up to 24 hours and under conditions of changing temperature (20^40 °C) and humidity,
Tylan Corp., 19220 S. Normandie Ave., Torrance, CA 90502, Model FC-260, or equivalent.
7.1.1.5 Particulate Matter Filter. 2-jj.m sintered stainless steel in-line filter, Nupro Co., 4800 E. 345th
St., Willoughby, OH 44094, Model SS-2F-K4-2, or equivalent.
7.1.1.6 Electronic Timer. For unattended sample collection, Paragon Elect. Co., 606 Parkway Blvd., P.O.
Box 28, Twin Rivers, WI 54201, Model 7008-00, or equivalent.
7.1.1.7 Solenoid Valve. Electrically-operated, bi-stable solenoid valve, Skinner Magnelatch Valve, New
Britain, CT, Model V5RAM49710, with Viton® seat and o-rings. A Skinner Magnelatch valve is used for
purposes of illustration only in Figures 2 and 3.
7.1.1.8 Chromatographic Grade Stainless Steel Tubing and Fittings. For interconnections, Alltech
Associates, 2051 Waukegan Rd., Deerfield, IL 60015, Cat. #8125, or equivalent. All such materials in contact
with sample, analyte, and support gases prior to analysis should be chromatographic grade stainless steel.
7.1.1.9 Thermostatically Controlled Heater. To maintain temperature inside insulated sampler
enclosure above ambient temperature, Watlow Co., Pfafftown, NC, Part 04010080, or equivalent.
7.1.1.10 Heater Thermostat. Automatically regulates heater temperature, Elmwood Sensors, Inc., 500
Narragansett Park Dr., Pawtucket, RI 02861, Model 3455-RC-0100-0222, or equivalent.
7.1.1.11 Fan. For cooling sample system, EG&G Rotron, Woodstock, NY, Model SUZAI, or equivalent.
7.1.1.12 Fan Thermostat. Automatically regulates fan operation, Elmwood Sensors, Inc., Pawtucket, RI,
Model 3455-RC-0100-0244, or equivalent.
7.1.1.13 Maximum-Minimum Thermometer. Records highest and lowest temperatures during sampling
period, Thomas Scientific, Brooklyn Thermometer Co., Inc., P/N 9327H30, or equivalent.
7.1.1.14 Stainless Steel Shut-Off Valve. Leak free, for vacuum/pressure gauge.
7.1.1.15 Auxiliary Vacuum Pump. Continuously draws ambient air through the inlet manifold at 10
L/min. or higher flow rate. Sample is extracted from the manifold at a lower rate, and excess air is exhausted.
[Note: The use of higher inlet flow rates dilutes any contamination present in the inlet and reduces the
possibility of sample contamination as a result of contact with active adsorption sites on inlet walls.]
Page 14A-8
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
7.1.1.16 Elapsed Time Meter. Measures duration of sampling, Conrac, Cramer Div., Old Saybrook, CT,
Type 6364, P/N 10082, or equivalent.
7.1.1.17 Optional Fixed Orifice, Capillary, or Adjustable Micrometering Valve. May be used in lieu
of the electronic flow controller for grab samples or short duration time-integrated samples. Usually appropriate
only in situations where screening samples are taken to assess future sampling activity.
7.1.2 Pressurized (see Figure 2 With Metal Bellows Type Pump and Figure 3).
7.1.2.1 Sample Pump. Stainless steel, metal bellows type, Metal Bellows Corp., 1075 Providence
Highway, Sharon, MA 02067, Model MB-151, or equivalent, capable of 2 atmospheres output pressure. Pump
must be free of leaks, clean, and uncontaminated by oil or organic compounds.
[Note: An alternative sampling system has been developed by Dr. R. Rasmussen, The Oregon Graduate
Institute of Science and Technology, 20000 N.W. Walker Rd., Beaverton, Oregon 97006, 503-690-1077,
(17,18) and is illustrated in Figure 3. This flow system uses, in order, a pump, a mechanical flow regulator,
and a mechanical compensation flow restrictive device. In this configuration the pump is purged with a large
sample flow, thereby eliminating the need for an auxiliary vacuum pump to flush the sample inlet.
Interferences using this configuration have been minimal.]
7.1.2.2 Other Supporting Materials. All other components of the pressurized sampling system (see
Figure 2 with metal bellows type pump and Figure 3) are similar to components discussed in Sections 7.1.1.1
through 7.1.1.16.
7.2 Sample Analysis
7.2.1 GC/MS/SCAN Analytical System (see Figure 4).
7.2.1.1 Gas Chromatograph. Capable of subambient temperature programming for the oven, with other
generally standard features such as gas flow regulators, automatic control of valves and integrator, etc. Flame
ionization detector optional, Hewlett Packard, Rt. 41, Avondale, PA 19311, Model 5880A, with oven temperature
control and Level 4 BASIC programming, or equivalent. The GS/MS/SCAN analytical system must be capable
of acquiring and processing data in the MS/SCAN mode.
7.2.1.2 Chromatographic Detector. Mass-selective detector, Hewlett Packard, 3000-T Hanover St., 9B,
Palo Alto, CA 94304, Model HP-5970 MS, or equivalent, equipped with computer and appropriate software,
Hewlett Packard, 3000-T Hanover St., 9B, Palo Alto, CA 94304, HP-216 Computer, Quicksilver MS software,
Pascal 3.0, mass storage 9133 HP Winchester with 3.5 inch floppy disk, or equivalent. The GC/MS is set in the
SCAN mode, where the MS screens the sample for identification and quantitation of VOC species.
7.2.1.3 Cryogenic Trap with Temperature Control Assembly. Refer to Section 10.1.1.3 for complete
description of trap and temperature control assembly, Graseby, 500 Technology Ct., Smyrna, GA 30082) Model
320-01, or equivalent.
7.2.1.4 Electronic Mass Flow Controllers (3). Maintain constant flow (for carrier gas and sample gas)
and to provide analog output to monitor flow anomalies, Tylan Model 260, 0-100 mL/min, or equivalent.
7.2.1.5 Vacuum Pump. General purpose laboratory pump, capable of drawing the desired sample volume
through the cryogenic trap, Thomas Industries, Inc., Sheboygan, WI, Model 107BA20, or equivalent.
7.2.1.6 Chromatographic Grade Stainless Steel Tubing and Stainless Steel Plumbing Fittings. Refer
to Section 7.1.1.8 for description.
7.2.1.7 Chromatographic Column. To provide compound separation such as shown in Table 5. Hewlett
Packard, Rt. 41, Avondale, PA 19311. Typical GC column for this application is OV-1 capillary column,
0.32-mm x 50 m with 0.88-,/m crosslinked methyl silicone coating, or equivalent.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-9
-------
Method TO-14A
VOCs
7.2.1.8 Stainless Steel Vacuum/Pressure Gauge (Optional). Capable of measuring vacuum (-101.3
to 0 kPa) and pressure (0-206 kPa) in the sampling system, Matheson, P.O. Box 136, Morrow, GA 30200, Model
63-3704, or equivalent. Gauges should be tested clean and tight.
7.2.1.9 Stainless Steel Cylinder Pressure Regulators. Standard, two-stage cylinder pressure gauges for
helium, zero air and hydrogen gas cylinders.
7.2.1.10 Gas Purifiers (3). Used to remove organic impurities and moisture from gas streams, Hewlett
Packard, Rt. 41, Avondale, PA 19311, P/N 19362 - 60500, or equivalent.
7.2.1.11 Low Dead-Volume Tee (optional). Used to split the exit flow from the GC column, Alltech
Associates, 2051 Waukegan Rd., Deerfield, IL 60015, Cat. #5839, or equivalent.
7.2.1.12 Nafion® Dryer. Consisting of Nafion tubing coaxially mounted within larger tubing, Perma Pure
Products, 8 Executive Drive, Toms River, NJ 08753, Model MD-125-48, or equivalent. Refer to Section
10.1.1.2 for description.
7.2.1.13 Six-Port Gas Cromatographic Valve. Seismograph Service Corp., Tulsa, OK, Seiscor
Model VIII, or equivalent.
7.2.1.14 Chart Recorder (optional). Compatible with the detector output signal to record optional FID
detector response to the sample.
7.2.1.15 Electronic Integrator (optional). Compatible with the detector output signal of the FID and
capable of integrating the area of one or more response peaks and calculating peak areas corrected for baseline
drift.
7.2.2 GC/MS/SIM Analytical System (see Figure 4).
7.2.2.1 The GC/MS/SIM analytical system must be capable of acquiring and processing data in the MS-
SIM mode.
7.2.2.2 All components of the GC/MS/SIM system are identical to Sections 7.2.1.1 through 7.2.1.15.
7.2.3 GC-Multidetector Analytical System (see Figure 5 and Figure 6).
7.2.3.1 Gas Chromatograph with Flame Ionization and Electron Capture Detectors
(Photoionization Detector Optional). Capable of sub-ambient temperature programming for the oven and
simultaneous operation of all detectors, and with other generally standard features such as gas flow regulators,
automatic control of valves and integrator, etc., Hewlett Packard, Rt. 41, Avondale, PA 19311, Model 5990A,
with oven temperature control and Level 4 BASIC programming, or equivalent.
7.2.3.2 Chart Recorders. Compatible with the detector output signals to record detector response tot he
sample.
7.2.3.3 Electronic Integrator. Compatible with the detector output signals and capable of integrating
the area of one or more response peaks and calculating peak areas corrected for baseline drift.
7.2.3.4 Six-Port Gas Chromatographic Valve. See Section 7.2.1.13.
7.2.3.5 Cryogenic Trap with Temperature Control Assembly. Refer to Section 10.1.1.3 for complete
description of trap and temperature control assembly, Graseby, 500 Technology Ct., Smyrna, GA 30082, Model
320-01, or equivalent.
7.2.3.6 Electronic Mass Flow Controllers (3). Maintain constant flow (for carrier gas, nitrogen make-up
gas and sample gas) and to provide analog output to monitor flow anomalies, Tylan Model 260, 0-100 mL/min,
or equivalent.
7.2.3.7 Vacuum Pump. General purpose laboratory pump, capable of drawing the desired sample volume
through the cryogenic trap (see Section 7.2.1.6 for source and description).
7.2.3.8 Chromatographic Grade Stainless Steel Tubing and Stainless Steel Plumbing Fittings. Refer
to Section 7.1.1.8 for description.
7.2.3.9 Chromatographic Column. To provide compound separation such as shown in Table 7, Hewlett
Packard, Rt. 41, Avondale, PA 19311. Typical GC column for this application is OV-1 capillary column, 0.32
mm x 50 m with 0.88 um crosslinked methyl silicone coating, or equivalent.
Page 14A-10
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
[Note: Other columns (e.g., DB-624) can be used as long as the system meets user needs. The Wider
Megabore® column (i.e., 0.53-mm I.D.) is less susceptible to plugging as a result of trapped water, thus
eliminating the needfor Naflon® dryer in the analytical system. The Megabore® column has sample capacity
approaching that of a packed column, while retaining much of the peak resolution traits of narrower columns
(i.e., 0.32-mm I.D.).]
7.2.3.10 Vacuum/Pressure Gauges (3). Refer to Section 7.2.1.9 for description.
7.2.3.11 Cylinder Pressure Stainless Steel Regulators. Standard, two-stage cylinder regulators with
pressure gauges for helium, zero air, nitrogen, and hydrogen gas cylinders.
7.2.3.12 Gas Purifiers (4). Used to remove organic impurities and moisture from gas streams, Hewlett
Packard, Rt. 41, Avondale, PA 19311, P/N 19362 - 60500, or equivalent.
7.2.3.13 Low Dead-Volume Tee. Used to split (50/50) the exit flow from the GC column, Alltech
Associates, 2051 Waukegan Rd., Deerfield, IL 60015, Cat. #5839, or equivalent.
7.3 Canister Cleaning System (see Figure 7)
7.3.1 Vacuum Pump. Capable of evacuating sample canister(s) to an absolute pressure of <0.05 mm Hg.
7.3.2 Manifold. Stainless steel manifold with connections for simultaneously cleaning several canisters.
7.3.3 Shut-off Valve(s). Seven (7) on-off toggle valves.
7.3.4 Stainless Steel Vacuum Gauge. Capable of measuring vacuum in the manifold to an absolute
pressure of 0.05 mm Hg or less.
7.3.5 Cryogenic Trap (2 required). Stainless steel U-shaped open tubular trap cooled with liquid oxygen
or argon to prevent contamination from back diffusion of oil from vacuum pump and to provide clean, zero air
to sample canister(s).
7.3.6 Stainless Steel Pressure Gauges (2). 0-345 kPa (0-50 psig) to monitor zero air pressure.
7.3.7 Stainless Steel Flow Control Valve. To regulate flow of zero air into canister(s).
7.3.8 Humidifier. Pressurizable water bubbler containing high performance liquid chromatography (HPLC)
grade deionized water or other system capable of providing moisture to the zero air supply.
7.3.9 Isothermal Oven (optional). For heating canisters, Fisher Scientific, Pittsburgh, PA, Model 349, or
equivalent.
7.4 Calibration System and Manifold (see Figure 8)
7.4.1 Calibration Manifold. Glass manifold, (1.25-cm I.D. x 66-cm) with sampling ports and internal
baffles for flow disturbance to ensure proper mixing.
7.4.2 Humidifier. 500-mL impinger flask containing HPLC grade deionized water.
7.4.3 Electronic Mass Flow Controllers. One 0 to 5 L/min and one 0 to 50 mL/min, Tylan Corporation,
23301-TS Wilmington Ave., Carson, CA 90745, Model 2160, or equivalent.
7.4.4 Teflon® Filter(s). 47-mm Teflon® filter for particulate control, best source.
8. Reagents and Materials
8.1 Gas Cylinders of Helium, Hydrogen, Nitrogen, and Zero Air. Ultrahigh purity grade, best source.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-11
-------
Method TO-14A
VOCs
8.2 Gas Calibration Standards. Cylinder(s) containing approximately 10 ppmv of each of the following
compounds of interest:
vinyl chloride
vinylidene chloride
1,1,2-trichloro-1,2,2-trifluoroethane
chloroform
1,2-dichloroethane
benzene
toluene
Freon 12
methyl chloride
1,2-dichloro-1,1,2,2-tetrafluoroethane
methyl bromide
ethyl chloride
Freon 11
dichloromethane
1,1 -dicholoroethane
cis-1,2-dicholoroethylene
1,2-dichloropropane
1,1,2-trichloroethane
1,2-dibromoethane
tetrachloroethylene
chlorobenzene
benzyl chloride
hexachloro-1,3 -butadiene
methyl chloroform
carbon tetrachloride
trichloroethylene
cis- 1,3-dichloropropene
trans-1,3-dichloropropene
ethylbenzene
o-xylene
m-xylene
p-xylene
styrene
1,1,2,2-tetrachloroethane
1,3,5 -trimethylbenzene
1,2,4-trimethylbenzene
m-dichlorobenzene
o-dichlorobenzene
p-dichlorobenzene
1,2,4-trichlorobenzene
The cylinder should be traceable to a National Institute of Standards and Technology (NIST) Standard Reference
Material (SRM). The components may be purchased in one cylinder or may be separated into different cylinders.
Refer to manufacturer's specification for guidance on purchasing and mixing VOCs in gas cylinders. Those
compounds purchased should match one's own TCL.
8.3 Cryogen. Liquid nitrogen (bp -195.8°C) or liquid argon (bp -185.7°C), best source.
8.4 Gas Purifiers. Connected in-line between hydrogen, nitrogen, and zero air gas cylinders and system inlet
line, to remove moisture and organic impurities from gas streams, Alltech Associates, 2051 Waukegan Rd.,
Deerfield, IL 60015, or equivalent.
8.5 Deionized Water. HPLC grade, ultrahigh purity (for humidifier), best source.
8.6 4-Bromofluorobenzene. Used for tuning GC/MS, best source.
8.7 Hexane. For cleaning sample system components, reagent grade, best source.
8.8 Methanol. For cleaning sampling system components, reagent garde, best source.
Page 14A-12
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
9. Sampling System
9.1 System Description
9.1.1 Subatmospheric Pressure Sampling [see Figure 2 (Without Metal Bellows Type Pump)].
9.1.1.1 In preparation for subatmospheric sample collection in a canister, the canister is evacuated to 0.05
mm Hg. When opened to the atmosphere containing the VOCs to be sampled, the differential pressure causes
the sample to flow into the canister. This technique may be used to collect grab samples (duration of 10 to 30
seconds) or time-integrated samples (duration of 12-24 hours) taken through a flow-restrictive inlet (e.g., mass
flow controller, critical orifice).
9.1.1.2 With a critical orifice flow restrictor, there will be a decrease in the flow rate as the pressure
approaches atmospheric. However, with a mass flow controller, the subatmospheric sampling system can
maintain a constant flow rate from full vacuum to within about 7 kPa (1.0 psig) or less below ambient pressure.
9.1.2 Pressurized Sampling [See Figure 2 (With Metal Bellows Type Pump)].
9.1.2.1 Pressurized sampling is used when longer-term integrated samples or higher volume samples are
required. The sample is collected in a canister using a pump and flow control arrangement to achieve a typical
103-206 kPa (15-30 psig) final canister pressure. For example, a 6-liter evacuated canister can be filled at 10
mL/min for 24 hours to achieve a final pressure of about 144 kPa (21 psig).
9.1.2.2 In pressurized canister samplings metal bellows type pump draws in ambient air from the
sampling manifold to fill and pressurize the sample canister.
9.1.3 All Samplers.
9.1.3.1 A flow control device is chosen to maintain a constant flow into the canister over the desired
sample period. This flow rate is determined so the canister is filled (to about 88.1 kPa for subatmospheric
pressure sampling or to about one atmosphere above ambient pressure for pressurized sampling) over the desired
sample period. The flow rate can be calculated by
F = P x V
T x 60
where:
F = flow rate, mL/min.
P = final canister pressure, atmospheres absolute. P is approximately equal to
kPa gauge + 1
101.2
V = volume of the canister, mL.
T = sample period, hours.
For example, if a 6-L canister is to be filled to 202 kPa (2 atmospheres) absolute pressure in 24 hours, the flow
rate can be calculated by
c 2 x 6000 „ - T , .
b = = 8.3 mL/min
24 x 60
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-13
-------
Method TO-14A
VOCs
9.1.3.2 For automatic operation, the timer is wired to start and stop the pump at appropriate times for the
desired sample period. The timer must also control the solenoid valve, to open the valve when starting the pump
and close the valve when stopping the pump.
9.1.3.3 The use of the Skinner Magnelateh valve avoids any substantial temperature rise that would occur
with a conventional, normally closed solenoid valve that would have to be energized during the entire sample
period. The temperature rise in the valve could cause outgassing of organic compounds from the Viton valve seat
material. The Skinner Magnelateh valve requires only a brief electrical pulse to open or close at the appropriate
start and stop times and therefore experiences no temperature increase. The pulses may be obtained either with
an electronic timer that can be programmed for short (5 to 60) seconds ON periods, or with a conventional
mechanical timer and a special pulse circuit. A simple electrical pulse circuit for operating the Skinner
Magnelateh solenoid valve with a conventional mechanical timer is illustrated in Figure 9(a). However, with this
simple circuit, the valve may operate unreliably during brief power interruptions or if the timer is manually
switched on and off too fast. A better circuit incorporating a time-delay relay to provide more reliable valve
operation is shown in Figure 9(b).
9.1.3.4 The connecting lines between the sample inlet and the canister should be as short as possible to
minimize their volume. The flow rate into the canister should remain relatively constant over the entire sampling
period. If a critical orifice is used, some drop in the flow rate may occur near the end of the sample period as the
canister pressure approaches the final calculated pressure.
9.1.3.5 As an option, a second electronic timer (see Section 7.1.1.6) may be used to start the auxiliary
pump several hours prior to the sampling period to flush and condition the inlet line.
9.1.3.6 Prior to field use, each sampling system must pass a humid zero air certification (see
Section 11.2.2). All plumbing should be check carefully for leaks. The canisters must also pass a humid zero
air certification before use (see Section 11.1).
9.2 Sampling Procedure
9.2.1 The sample canister should be cleaned and tested according to the procedure in Section 11.1.
9.2.2 A sample collection system is assembled as shown in Figure 2 (and Figure 3) and must meet
certification requirements as outlined in Section 11.2.3.
[Note: The sampling system should be contained in an appropriate enclosure.]
9.2.3 Prior to locating the sampling system, the user may want to perform "screening analyses" using a
portable GC system, as outlined in Appendix B, to determine potential volatile organics present and potential "hot
spots." The information gathered from the portable GC screening analysis would be used in developing a
monitoring protocol, which includes the sampling system location, based upon the "screening analysis" results.
9.2.4 After "screening analysis," the sampling system is located. Temperatures of ambient air and sampler
box interior are recorded on the Compendium Method TO-14A field test data sheet (FTDS), as illustrated in
Figure 10.
[Note: The following discussion is related to Figure 2.]
9.2.5 To verify correct sample flow, a "practice" (evacuated) canister is used in the sampling system.
[Note: For a subatmospheric sampler, the flow meter and practice canister are needed. For the pump-driven
system, the practice canister is not needed, as the flow can be measured at the outlet of the system.]
Page 14A-14
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
A certified mass flow meter is attached to the inlet line of the manifold, just in front of the filter. The canister
is opened. The sampler is turned on and the reading of the certified mass flow meter is compared to the sampler
mass flow controller. The valves should agree within ±10%. If not, the sampler mass flow meter needs to be
recalibrated or there is a leak in the system. This should be investigated and corrected.
[Note: Mass flow meter readings may drift. Check the zero reading carefully and add or subtract the zero
reading when reading or adjusting the sampler flow rate, to compensate for any zero drift.]
After two minutes, the desired canister flow rate is adjusted to the proper value (as indicated by the certified mass
flow meter) by the sampler flow control unit controller (e.g., 3.5 mL/min for 24 hr, 7.0 mL/min for 12 hr).
Record final flow under "CANISTER FLOW RATE," as provided in Figure 10.
9.2.6 The sampler is turned off and the elapsed time meter is reset to 000.0.
[Note: Any time the sampler is turned off wait at least 30 seconds to turn the sampler back on.]
9.2.7 The "practice" canister and certified mass flow meter are disconnected and a clean certified (see
Section 11.1) canister is attached to the system.
9.2.8 The canister valve and vacuum/pressure gauge valve are opened.
9.2.9 Pressure/vacuum in the canister is recorded on the canister sampling field data sheet (see Figure 10)
as indicated by the sampler vacuum/pressure gauge.
9.2.10 The vacuum/pressure gauge valve is closed and the maximum-minimum thermometer is reset to
current temperature. Time of day and elapsed time meter readings are recorded on the canister sampling field data
sheet.
9.2.11 The electronic timer is set to begin and stop the sampling period at the appropriate times. Sampling
commences and stops by the programmed electronic timer.
9.2.12 After the desired sampling period, the maximum, minimum, current interior temperature and current
ambient temperature are recorded on the sampling field data sheet. The current reading from the flow controller
is recorded.
9.2.13 At the end of the sampling period, the vacuum/pressure gauge valve on the sampler is briefly opened
and closed and the pressure/vacuum is recorded on the sampling FTDS. Pressure should be close to desired
pressure.
[Note: For a subatmospheric sampling system, if the canister is at atmospheric pressure when the field final
pressure check is performed, the sampling period may be suspect. This information should be noted on the
sampling FTDS.]
Time of day and elapsed time meter readings are also recorded.
9.2.14 The canister valve is closed. The sampling line is disconnected from the canister and the canister is
removed from the system. For a subatmospheric system, a certified mass flow meter is once again connected to
the inlet manifold in front of the in-line filter and a "practice" canister is attached to the Magnelatch valve of the
sampling system. The final flow rate is recorded on the canister sampling field data sheet (see Figure 10).
[Note: For a pressurized system, the final flow may be measured directly.]
The sampler is turned off.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-15
-------
Method TO-14A
VOCs
9.2.15 An identification tag is attached to the canister. Canister serial number, sample number, location, and
date are recorded on the tag. Complete the Chain-of-Custody (COC) for the canister and ship back to the
laboratory for analysis.
10. Analytical System (see Figures 4, 5 and 6)
[Note: The following section relates to the use of the linear quadrupole MS technology as the detector. The
ion-trap technology is as applicable to the detection of VOCs from a specially-treated canister. EPA
developed this method using the linear quadrupole MS, as part of it's air toxics field and laboratory
monitoring programs over the last several years. Modifications to these procedures may be necessary if other
technology is utilized.]
10.1 System Description
10.1.1 GC/MS/SCAN System.
10.1.1.1 The analytical system is comprised of a GC equipped with a mass-selective detector set in the
SCAN mode (see Figure 4). All ions are scanned by the MS repeatedly during the GC run. The system includes
a computer and appropriate software for data acquisition, data reduction, and data reporting. A 400 mL air
sample is collected from the canister into the analytical system. The sample air is first passed through a Nafion®
dryer, through the 6-port chromatographic valve, then routed into a cryogenic trap.
[Note: While the GC-multidetector analytical system does not employ a Nafion® dryer for drying the sample
gas stream, it is used here because the GC/MS system utilizes a larger sample volume and is far more sensitive
to excessive moisture than the GC-multidetector analytical system. Moisture can adversely affect detector
precision. The Nafion® dryer also prevents freezing of moisture on the 0.32-mm I.D. column, which may
cause column blockage and possible breakage.]
The trap is heated (-160°C to 120°C in 60 sec) and the analyte is injected onto the OV-1 capillary column (0.32-
mm x 50-m).
[Note: Rapid heating of the trap provides efficient transfer of the sample components onto the gas
chromatographic column.]
Upon sample injection unto the column, the MS computer is signaled by the GC computer to begin detection of
compounds which elute from the column. The gas stream from the GC is scanned within a preselected range of
atomic mass units (amu). For detection of compounds in Table 1, the range should be 18 to 250 amu, resulting
in a 1.5 Hz repetition rate. Six (6) scans per eluting chromatographic peak are provided at this rate. The 10-15
largest peaks are chosen by an automated data reduction program, the three scans nearest the peak apex are
averaged, and a background subtraction is performed. A library search is then performed and the top ten best
matches for each peak are listed. A qualitative characterization of the sample is provided by this procedure. A
typical chromatogram of VOCs determined by GC/MS/SCAN is illustrated in Figure 11(a).
10.1.1.2 A Nafion® permeable membrane dryer is used to remove water vapor selectively from the sample
stream. The permeable membrane consists of Nafion® tubing (a copolymer of tetrafluoroethylene and
fluorosulfonyl monomer) that is coaxially mounted within larger tubing. The sample stream is passed through
the interior of the Nafion® tubing, allowing water (and other light, polar compounds) to permeate through the
walls into the dry purge stream flowing through the annular space between the Nafion® and outer tubing.
Page 14A-16
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
[Note: To prevent excessive moisture build-up and any memory effects in the dryer, a clean-up procedure
involving periodic heating of the dryer (100° C for 20 minutes) while purging with dry zero air (-500 mL/min)
should be implemented as part of the user's SOP manual. The clean-up procedure is repeated during each
analysis (7). Studies have indicated no substantial loss of targeted VOCs utilizing the above clean-up
procedure (7). However, use of the cleanup procedure for compounds other than those on the TCL can lead
to loss of sample integrity (19). This clean-up procedure is particularly useful when employing cryogenic
preconcentration of VOCs with subsequent GC analysis using a 0.32-mm I.D. column because excess
accumulated water can cause trap and column blockage and also adversely affect detector precision. In
addition, the improvement in water removal from the sampling stream will allow analyses of much larger
volumes of sample air in the event that greater system sensitivity is required for targeted compounds.]
10.1.1.3 The packed metal tubing used for reducing temperature trapping of VOCs is shown in Figure 12.
The cooling unit is comprised of a 0.32-cm outside diameter (O.D.) nickel tubing loop packed with 60-80 mesh
Pyrex® beads, Nutech Model 320-01, or equivalent. The nickel tubing loop is wound onto a cylindrically formed
tube heater (-250 watt). A cartridge heater (-25 watt) is sandwiched between pieces of aluminum plate at the
trap inlet and outlet to provide additional heat to eliminate cold spots in the transfer tubing. During operation,
the trap is inside a two-section stainless steel shell which is well insulated. Rapid heating (-150 to +100°C in
55 s) is accomplished by direct thermal contact between the heater and the trap tubing. Cooling is achieved by
vaporization of the cryogen. In the shell, efficient cooling (+120 to -150° C in 225 s) is facilitated by confining
the vaporized cryogen to the small open volume surrounding the trap assembly. The trap assembly and
chromatographic valve are mounted on a baseplate fitted into the injection and auxiliary zones of the GC on an
insulated pad directly above the column oven for most commercially available GC systems.
[Note: Alternative trap assembly and connection to the GC may be used depending on the user's
requirements.]
The carrier gas line is connected to the injection end of the analytical column with a zero-dead-volume fitting that
is usually held in the heated zone above the GC oven. A 15-cm x 15-cm x 24-cm aluminum box is fitted over
the sample handling elements to complete the package. Vaporized cryogen is vented through the top of the box.
10.1.1.4 As an option, the analyst may wish to split the gas stream exiting the column with a low dead-
volume tee, passing one-third of the sample gas (~1.0 mL/min) to the mass-selective detector and the remaining
two-thirds (~2.0 mL/min) through an FID, as illustrated as an option in Figure 4. The use of the specific detector
(MS/SCAN) coupled with the non-specific detector (FID) enables enhancement of data acquired from a single
analysis. In particular, the FID provides the user:
• Semi-real time picture of the progress of the analytical scheme.
• Confirmation by the concurrent MS analysis of other labs that can provide only FID results.
• Ability to compare GC/FID with other analytical laboratories with only GC/FID capability.
10.1.2 GC/MS/SIM System
10.1.2.1 The analytical system is comprised of a GC equipped with an OV-1 capillary column (0.32-mm
x 50-m) and a mass-selective detector set in the SIM mode (see Figure 4). The GC/MS is set up for automatic,
repetitive analysis. The system is programmed to acquire data for only the target compounds and to disregard
all others. The sensitivity is 0.1 ppbv for a 250 mL air sample with analytical precision of about 5% relative
standard deviation. Concentration of compounds based upon a previously installed calibration table is reported
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-17
-------
Method TO-14A
VOCs
by an automated data reduction program. A Nafion® dryer is also employed by this analytical system prior to
cryogenic preconcentration; therefore, many polar compounds are not identified by this procedure.
10.1.2.2 SIM analysis is based on a combination of retention times and relative abundances of selected
ions (see Table 2). These qualifiers are stored on the hard disk of the GC/MS computer and are applied for
identification of each chromatographic peak. The retention time qualifier is determined to be ± 0.10 minute of
the library retention time of the compound. The acceptance level for relative abundance is determined to be ±
15% of the expected abundance, except for vinyl chloride and methylene chloride, which is determined to be ±
25%. Three ions are measured for most of the forty compounds. When compound identification is made by the
computer, any peak that fails any of the qualifying tests is flagged (e.g., with an *). All the data should be
manually examined by the analyst to determine the reason for the flag and whether the compound should be
reported as found. While this adds some subjective judgment to the analysis, computer-generated identification
problems can be clarified by an experienced operator. Manual inspection of the quantitative results should also
be performed to verify concentrations outside the expected range. A typical chromatogram of VOCs determined
by GC/MS/SIM mode is illustrated in Figure 11(b).
10.1.3 GC-Multidetector (GC/FID/ECD) System with Optional PID.
10.1.3.1 The analytical system (see Figure 5) is comprised of a gas chromatograph equipped with a
capillary column and electron capture and flame ionization detectors (see Figure 5). In typical operation, sample
air from pressurized canisters is vented past the inlet to the analytical system from the canister at a flow rate of
75 mL/min. For analysis, only 35 mL/min of sample gas is used, while excess is vented to the atmosphere. Sub-
ambient pressure canisters are connected directly to the inlet and air is pulled through a trap by a downstream
vacuum. The sample gas stream is routed through a six port chromatographic valve and into the cryogenic trap
for a total sample volume of 490 mL.
[Note: This represents a 14 minute sampling period at a rate of 35 mL/min.]
The trap (see Section 10.1.1.3) is cooled to -150°C by controlled release of acryogen. VOCs are condensed on
the trap surface while N2, Q,, and other sample components are passed to the pump. After the organic
compounds are concentrated, the valve is switched and the trap is heated. The revolatilized compounds are
transported by helium carrier gas at a rate of 4 mL/min to the head of the Megabore® OV-1 capillary column
(0.53-mm x 30-m). Since the column initial temperature is at -50°C, the VOCs are cryofocussed on the head of
the column. Then, the oven temperature is programmed to increase and the VOCs in the carrier gas are
chromatographically separated. The carrier gas containing the separated VOCs is then directed to two parallel
detectors at a flow rate of 2 mL/min each. The detectors sense the presence of the speciated VOCs, and the
response is recorded by either a strip chart recorder or a data processing unit.
10.1.3.2 Typical chromatograms of VOCs determined by the GC/FID/ECD analytical system are
illustrated in Figures 11(c) and 11(d), respectively.
10.1.3.3 Helium is used as the carrier gas (~4 mL/min) to purge residual air from the trap at the end of
the sampling phase and to carry the revolatilized VOCs through the Megabore® GC column. Moisture and
organic impurities are removed from the helium gas stream by a chemical purifier installed in the GC (see Section
7.2.1.11). After exiting the OV-1 Megabore® column, the carrier gas stream is split to the two detectors at rates
of ~2 mL/min each.
10.1.3.4 Gas scrubbers containing Drierite® or silica gel and 5A molecular sieve are used to remove
moisture and organic impurities from the zero air, hydrogen, and nitrogen gas streams.
[Note: Purity of gas purifiers is checked prior to use by passing humid zero-air through the gas purifier and
analyzing according to Section 11.2.2.]
Page 14A-18
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
10.1.3.5 All lines should be kept as short as practical. All tubing used for the system should be
chromatographic grade stainless steel connected with stainless steel fittings. After assembly, the system should
be checked for leaks according to manufacturer's specifications.
10.1.3.6 The FID burner air, hydrogen, nitrogen (make-up), and helium (carrier) flow rates should be set
according to the manufacturer's instructions to obtain an optimal FID response while maintaining a stable flame
throughout the analysis. Typical flow rates are: burner air, 450 mL/min; hydrogen, 30 mL/min; nitrogen, 30
mL/min; helium, 2 mL/min.
10.1.3.7 The ECD nitrogen make-up gas and helium carrier flow rates should be set according to
manufacturer's instructions to obtain an optimal ECD response. Typical flow rates are: nitrogen, 76 mL/min and
helium, 2 mL/min.
10.1.3.8 The GC/FID/ECD could be modified to include a PID (see Figure 6) for increased sensitivity (20).
In the photoionization process, a molecule is ionized by ultraviolet light as follows: R + hv • R + e-, where R+
is the ionized species and a photon is represented by hv, with energy less than or equal to the ionization potential
of the molecule. Generally all species with an ionization potential less than the ionization energy of the lamp are
detected. Because the ionization potential of all major components of air (02, N2, CO, C02, and H20) is greater
than the ionization energy of lamps in general use, they are not detected. The sensor is comprised of an argon-
filled, ultraviolet (UV) light source where a portion of the organic vapors are ionized in the gas stream. A pair
of electrodes are contained in a chamber adjacent to the sensor. When a potential gradient is established between
the electrodes, any ions formed by the absorption of UV light are driven by the created electric field to the
cathode, and the current (proportional to the organic vapor concentration) is measured. The PID is generally used
for compounds having ionization potentials less than the ratings of the ultraviolet lamps. This detector is used
for determination of most chlorinated and oxygenated hydrocarbons, aromatic compounds, and high molecular
weight aliphatic compounds. Because the PID is insensitive to methane, ethane, carbon monoxide, carbon
dioxide, and water vapor, it is an excellent detector. The electron volt rating is applied specifically to the
wavelength of the most intense emission line of the lamp's output spectrum. Some compounds with ionization
potentials above the amp rating can still be detected due to the presence of small quantities of more intense light.
A typical system configuration associated with the GC/FID/ECD/PID is illustrated in Figure 6.
10.2 GC/MS/SCAN/SIM System Performance Criteria
10.2.1 GC/MS System Operation.
10.2.1.1 Prior to analysis, the GC/MS system is assembled and checked according to manufacturer's
instructions.
10.2.1.2 Table 3.0 outlines general operating conditions for the GC/MS/SCAN/SIM system with optional
FID.
10.2.1.3 The GC/MS system is first challenged with humid zero air (see Section 11.2.2).
10.2.1.4 The GC/MS and optional FID system is acceptable if it contains less than 0.2 ppbv of targeted
VOCs.
10.2.2 Daily GC/MS Tuning (see Figure 13)
10.2.2.1 At the beginning of each day or prior to a calibration, the GC/MS system must be tuned to verify
that acceptable performance criteria are achieved.
10.2.2.2 For tuning the GC/MS, a cylinder containing 4-bromofluorobenzene (4-BFB) is introduced via
a sample loop valve injection system.
[Note: Some systems allow auto-tuning to facilitate this process.]
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-19
-------
Method TO-14A
VOCs
The key ions and ion abundance criteria that must be met are illustrated in Table 4. Analysis should not begin
until all those criteria are met.
10.2.2.3 The GC/MS tuning standard could also be used to assess GC column performance
(chromatographic check) and as an internal standard. Obtain a background correction mass spectra of 4-BFB
and check that all key ions criteria are met. If the criteria are not achieved, the analyst must retune the mass
spectrometer and repeat the test until all criteria are achieved.
10.2.2.4 The performance criteria must be achieved before any samples, blanks or standards are analyzed.
If any key ion abundance observed for the daily 4-BFB mass tuning check differs by more than 10% absolute
abundance from that observed during the previous daily tuning, the instrument must be retuned or the sample
and/or calibration gases reanalyzed until the above condition is met.
10.2.3 GC/MS Calibration (see Figure 13)
[Note: Initial and routine calibration procedures are illustrated in Figure 13. J
10.2.3.1 Initial Calibration. Initially, a multipoint dynamic calibration (three levels plus humid zero air)
is performed on the GC/MS system, before sample analysis, with the assistance of a calibration system (see
Figure 8). The calibration system uses NIST traceable standards [containing a mixture of the targeted VOCs at
nominal concentrations of 10 ppmv in nitrogen (see Section 8.2)] as working standards to be diluted with humid
zero air. The contents of the working standard cylinder(s) are metered (~2 mL/min) into the heated mixing
chamber where they are mixed with a 2-L/min humidified zero air gas stream to achieve a nominal 10 ppbv per
compound calibration mixture (see Figure 8). This nominal 10 ppbv standard mixture is allowed to flow and
equilibrate for a minimum of 30 minutes. After the equilibration period, the gas standard mixture is sampled and
analyzed by the real-time GC/MS system [see Figure 8(a) and Section 7.2.1], The results of the analyses are
averaged, flow audits are performed on the mass flow meters and the calculated concentration compared to
generated values. After the GC/MS is calibrated at three concentration levels, a second humid zero air sample
is passed through the system and analyzed. The second humid zero air test is used to verify that the GC/MS
system is certified clean (<0.2 ppbv of target compounds).
As an alternative, a multipoint humid static calibration (three levels plus zero humid air) can be performed on
the GC/MS system. During the humid static calibration analyses, three (3) specially-treated canisters are filled
each at a different concentration between 1-20 ppbv from the calibration manifold using a pump and mass flow
control arrangement [see Figure 8(c)]. The canisters are then delivered to the GC/MS to serve as calibration
standards. The canisters are analyzed by the MS in the SIM mode, each analyzed twice.
The expected retention time and ion abundance (see Table 2 and Table 5) are used to verify proper operation of
the GC/MS system. A calibration response factor is determined for each analyte, as illustrated in Table 5, and
the computer calibration table is updated with this information, as illustrated in Table 6. The relative standard
deviation (RSD) of the response factors should be <30% for the curve to be acceptable. If the RSD is >30%,
recalibration is required. The samples are calculated using the mean of the response factors.
10.2.3.2 Routine Calibration. The GC/MS system is calibrated daily (and before sample analysis) with
a one-point calibration. The GC/MS system is calibrated either with the dynamic calibration procedure [see
Figure 8(a)] or with a 6-L specially prepared passivated canister filled with humid calibration standards from the
calibration manifold (see Section 10.2.3.2). After the single point calibration, the GC/MS analytical system is
challenged with a humidified zero gas stream to insure the analytical system returns to specification (<0.2 ppbv
of selective organics). The relative percent difference (RPD) of each response factor from the mean response
factor of the initial calibration curve should be <30% for continued use of the mean response factors. If the RPD
is >30%, recalibration is required.
Page 14A-20
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
10.3 GC/FID/ECD System Performance Criteria (With Optional PID System) [see Figure 14])
10.3.1 Humid Zero Air Certification
10.3.1.1 Before system calibration and sample analysis, the GC/FID/ECD analytical system is assembled
and checked according to manufacturer's instructions.
10.3.1.2 The GC/FID/ECD system is first challenged with humid zero air (see Section 11.2.2) and
monitored.
10.3.1.3 Analytical systems contaminated with <0.2 ppbv of targeted VOCs are acceptable.
10.3.2 GC Retention Time Windows Determination (see Table 7)
10.3.2.1 Before analysis can be performed, the retention time windows must be established for each
analyte.
10.3.2.2 Make sure the GC system is within optimum operating conditions.
10.3.2.3 Make three injections of the standard containing all compounds for retention time window
determination.
[Note: The retention time window must be established for each analyte every 72 hours during continuous
operation.]
10.3.2.4 Calculate the standard deviation of the three absolute retention times for each single component
standard. The retention window is defined as the mean plus or minus three times the standard deviation of the
individual retention times for each standard. In those cases where the standard deviation for a particular standard
is zero, the laboratory must substitute the standard deviation of a closely-eluting, similar compound to develop
a valid retention time window.
10.3.2.5 The laboratory must calculate retention time windows for each standard (see Table 7) on each
GC column, whenever a new GC column is installed or when major components of the GC are changed. The data
must be noted and retained in a notebook by the laboratory as part of the user SOP and as a quality assurance
check of the analytical system.
10.3.3 GC Calibration
[Note: Initial and routine calibration procedures are illustrated in Figure 14.]
10.3.3.1 Initial Calibration. Initially, a multipoint dynamic calibration (three levels plus humid zero air)
is performed on the GC/FID/ECD system, before sample analysis, with the assistance of a calibration system (see
Figure 8). The calibration system uses NIST traceable standards or [containing a mixture of the targeted VOCs
at nominal concentrations of 10 ppmv in nitrogen (see Section 8.2)] as working standards to be diluted with
humid zero air. The contents of the working standard cylinders are metered (2 mL/min) into the heated mixing
chamber where they are mixed with a 2-L/min humidified zero air stream to achieve a nominal 10 ppbv per
compound calibration mixture (see Figure 8). This nominal 10 ppbv standard mixture is allowed to flow and
equilibrate for an appropriate amount of time. After the equilibration period, the gas standard mixture is sampled
and analyzed by the GC/MS system [see Figure 8(a)]. The results of the analyses are averaged, flow audits are
performed on the mass flow controllers used to generate the standards and the appropriate response factors
(concentration/area counts) are calculated for each compound, as illustrated in Table 5. The relative standard
deviation (RSD) of the response factors should be <30% for the curve to be acceptable. If the RSD is >30%,
recalibration is required. The samples are calculated using the mean of the response factors.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-21
-------
Method TO-14A
VOCs
[Note: GC/FIDs are linear in the 1-20ppbv range and may not require repeated multipoint calibrations;
whereas, the GC/ECD will require frequent linearity evaluation.]
Table 5 outlines typical calibration response factors and retention times for 40 VOCs. After the GC/FID/ECD
is calibrated at the three concentration levels, a second humid zero air sample is passed through the system and
analyzed. The second humid zero air test is used to verify that the GC/FID/ECD system is certified clean (<0.2
ppbv of target compounds).
10.3.3.2 Routine Calibration. A one point calibration is performed daily on the analytical system to
verify the initial multipoint calibration (see Section 10.3.3.1). The analyzers (GC/FID/ECD) are calibrated
(before sample analysis) using the static calibration procedures (see Section 10.2.3.2) involving pressurized gas
cylinders containing low concentrations of the targeted VOCs (~ 10 ppbv) in nitrogen. After calibration, humid
zero air is once again passed through the analytical system to verify residual VOCs are not present. The relative
percent difference (RPD) of each response factor from the mean response factor of the initial calibration curve
should be <30% for continued use of the mean response factors. If the RPD is >30%, recalibration is required.
10.3.4 GC/FID/ECD/PID System Performance Criteria
10.3.4.1 As an option, the user may wish to include a PID to assist in peak identification and increase
sensitivity.
10.3.4.2 This analytical system has been used in U.S. Environmental Protection Agency's Urban Air Toxic
Monitoring Program (UATMP).
10.3.4.3 Preparation of the GC/FID/ECD/PID analytical system is identical to the GC/FID/ECD system
(see Section 10.3).
10.3.4.4 Table 8 outlines typical retention times (minutes) for selected organics using the
GC/FID/ECD/PID analytical system.
10.4 Analytical Procedures
10.4.1 Canister Receipt
10.4.1.1 The overall condition of each sample canister is observed. Each canister should be received with
an attached sample identification tag and FTDS. Complete the canister COC.
10.4.1.2 Each canister is recorded in the dedicated laboratory logbook. Also noted on the identification
tag are date received and initials of recipient.
10.4.1.3 The pressure of the canister is checked by attaching a pressure gauge to the canister inlet. The
canister valve is opened briefly and the pressure (kPa, psig) is recorded.
[Note: If pressure is <83 kPa (<12 psig), the user may wish to pressurize the canisters, as an option, with
zero grade nitrogen up to 137 kPa (20 psig) to ensure that enough sample is available for analysis. However,
pressurizing the canister can introduce additional error, increase the minimum detection limit (MDL), and
is time consuming. The user should weigh these limitations as part of his program objectives before
pressurizing.]
Final cylinder pressure is recorded on the canister FTDS (see Figure 10).
10.4.1.4 If the canister pressure is increased, a dilution factor (DF) is calculated and recorded on the
sampling data sheet.
Page 14A-22
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
Y
DF = —
X
where:
X:i = canister pressure absolute before dilution, kPa, psia.
Ya = canister pressure absolute after dilution, kPa, psia.
After sample analysis, detected VOC concentrations are multiplied by the dilution factor to determine
concentration in the sampled air.
10.4.2 GC/MS/SCAN Analysis (With Optional FID System)
10.4.2.1 The analytical system should be properly assembled, humid zero air certified (see Section 11.3),
operated (see Table 3), and calibrated for accurate VOC determination.
10.4.2.2 The mass flow controllers are checked and adjusted to provide correct flow rates for the system.
10.4.2.3 The sample canister is connected to the inlet of the GC/MS/SCAN (with optional FID) analytical
system. For pressurized samples, a mass flow controller is placed on the canister and the canister valve is opened
and the canister flow is vented past a tee inlet to the analytical system at a flow of 75 mL/min so that 35 mL/min
is pulled through the Nafion® dryer to the six-port chromatographic valve.
[Note: Flow rate is not as important as acquiring sufficient sample volume.]
Sub-ambient pressure samples are connected directly to the inlet.
10.4.2.4 The GC oven and cryogenic trap (inject position) are cooled to their set points of -50°C and
-15 00 C, respectively.
10.4.2.5 As soon as the cryogenic trap reaches its lower set point of -1500 C, the six-port chromatographic
valve is turned to its fill position to initiate sample collection.
10.4.2.6 A 10 minute collection period of canister sample is utilized.
[Note: 40 mL/min x 10 min = 400 mL sampled canister contents.]
10.4.2.7 After the sample is preconcentrated in the cryogenic trap, the GC sampling valve is cycled to the
inject position and the cryogenic trap is heated. The trapped analytes are thermally desorbed onto the head of the
OV-1 capillary column (0.31-mm I.D. x 50-m length). The GC oven is programmed to start at -50°C and after
2 min to heat to 150°C at a rate of 8°C per minute.
10.4.2.8 Upon sample injection onto the column, the MS is signaled by the computer to scan the eluting
carrier gas from 18 to 250 amu, resulting in a 1.5 Hz repetition rate. This corresponds to about 6 scans per
eluting chromatographic peak.
10.4.2.9 Primary identification is based upon retention time and relative abundance of eluting ions as
compared to the spectral library stored on the hard disk of the GC/MS data computer.
10.4.2.10 The concentration (ppbv) is calculated using the previously established response factors (see
Section 10.2.3.2), as illustrated in Table 5.
[Note: If the canister is diluted before analysis, an appropriate multiplier is applied to correct for the volume
dilution of the canister (see Section 10.4.1.4).]
January 1999 Compendium of Methods for Toxic Organic Air Pollutants Page 14A-23
-------
Method TO-14A
VOCs
10.4.2.11 The optional FID trace allows the analyst to record the progress of the analysis.
10.4.3 GC/MS/SIM Analysis (With Optional FID System).
10.4.3.1 When the MS is placed in the SIM mode of operation, the MS monitors only preselected ions,
rather than scanning all masses continuously between two mass limits.
10.4.3.2 As a result, increased sensitivity and improved quantitative analysis can be achieved.
10.4.3.3 Similar to the GC/MS/SCAN configuration, the GC/MC/SIM analysis is based on a combination
of retention times and relative abundances of selected ions (see Table 2 and Table 5). These qualifiers are stored
on the hard disk of the GC/MS computer and are applied for identification of each chromatographic peak. Once
the GC/MS/SIM has identified the peak, a calibration response factor is used to determine the analyte's
concentration.
10.4.3.4 The individual analyses are handled in three phases: data acquisition, data reduction, and data
reporting. The data acquisition software is set in the SIM mode, where specific compound fragments are
monitored by the MS at specific times in the analytical run. Data reduction is coordinated by the postprocessing
macro program that is automatically accessed after data acquisition is completed at the end of the GC run.
Resulting ion profiles are extracted, peaks are identified and integrated, and an internal integration report is
generated by the program. A reconstructed ion chromatogram for hardcopy reference is prepared by the program
and various parameters of interest such as time, date, and integration constants are printed. At the completion
of the macro program, the data reporting software is accessed. The appropriate calibration table (see Table 9)
is retrieved by the data reporting program from the computer's hard disk storage and the proper retention time
and response factor parameters are applied to the macro program's integration file. With reference to certain pre-
set acceptance criteria, peaks are automatically identified and quantified and a final summary report is prepared,
as illustrated in Table 10.
10.4.4 GC/FID/ECD Analysis (With Optional PID System)
10.4.4.1 The analytical system should be properly assembled, humid zero air certified (see Section 12.2)
and calibrated through a dynamic standard calibration procedure (see Section 10.3.2). The FID detector is lit and
allowed to stabilize.
10.4.4.2 Sixty-four minutes are required for each sample analysis: 15 min for system initialization, 14 min
for sample collection, 30 min for analysis, and 5 min for post-time, during which a report is printed.
[Note: This may vary depending upon system configuration and programming.]
10.4.4.3 The helium and sample mass flow controllers are checked and adjusted to provide correct flow
rates for the system. Helium is used to purge residual air from the trap at the end of the sampling phase and to
carry the revolatilized VOCs from the trap onto the GC column and into the FID/ECD. The hydrogen, burner
air, and nitrogen flow rates should also be checked. The cryogenic trap is connected and verified to be operating
properly while flowing cryogen through the system.
10.4.4.4 The sample canister is connected to the inlet of the GC/FID/ECD analytical system. The canister
valve is opened and the canister flow is vented past a tee inlet to the analytical system at 75 mL/min using a mass
flow controller. During analysis, 35 mL/min of sample gas is pulled through the six-port chromatographic valve
and routed through the trap at the appropriate time while the extra sample is vented. The VOCs are condensed
in the trap while the excess flow is exhausted through an exhaust vent, which assures that the sample air flowing
through the trap is at atmospheric pressure.
10.4.4.5 The six-port valve is switched to the inject position and the canister valve is closed.
10.4.4.6 The electronic integrator is started.
10.4.4.7 After the sample is preconcentrated on the trap, the trap is heated and the VOCs are thermally
desorbed onto the head of the capillary column. Since the column is at -50°C, the VOCs are cryofocussed on the
Page 14A-24
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
column. Then, the oven temperature (programmed) increases and the VOCs elute from the column to the parallel
FID/ECD assembly.
10.4.4.8 The peaks eluting from the detectors are identified by retention time (see Table 7 and Table 8),
while peak areas are recorded in area counts. Typical response of the FID and ECD, respectively, for the forty
(40) targeted VOCs identified in Compendium Method TO-14A are illustrated in Figures 15 and 16, respectively.
[Note: Refer to Table 7 for peak number and identification.]
10.4.4.9 The response factors (see Section 10.3.3.1) are multiplied by the area counts for each peak to
calculate ppbv estimates for the unknown sample. If the canister is diluted before analysis, an appropriate
dilution multiplier (DF) is applied to correct for the volume dilution of the canister (see Section 10.4.1.4).
10.4.4.10 Each canister is analyzed twice and the final concentrations for each analyte are the averages
of the two analyses.
10.4.4.11 However, if the GC/FID/ECD analysis shows unexpected peaks which need further identification
and attention or overlapping peaks are discovered, eliminating possible quantitation, the sample should then be
subjected to a GC/MS/SCAN for positive identification and quantitation.
11. Cleaning and Certification Program
11.1 Canister Cleaning and Certification
11.1.1 All canisters must be clean and free of any contaminants before sample collection.
11.1.2 All canisters are leak tested by pressurizing them to approximately 206 kPa (-30 psig) with zero air.
[Note: The canister cleaning system in Figure 7 can be used for this task. The initial pressure is measured,
the canister value is closed, and the final pressure is checked after 24 hours. If leak tight, the pressure should
not vary more than ±13.8 kPa (± 2 psig) over the 24 hour period.]
11.1.3 A canister cleaning system may be assembled as illustrated in Figure 7. Cryogen is added to both the
vacuum pump and zero air supply traps. The canister(s) are connected to the manifold. The vent shut-off valve
and the canister valve(s) are opened to release any remaining pressure in the canister(s). The vacuum pump is
started and the vent shut-off valve is then closed and the vacuum shut-off valve is opened. The canister(s) are
evacuated to <0.05 mm Hg (for at least one hour).
[Note: On a daily basis or more often if necessary, the cryogenic traps should be purged with zero air to
remove any trapped water from previous canister cleaning cycles.]
11.1.4 The vacuum and vacuum/pressure gauge shut-off valves are closed and the zero air shut-off valve is
opened to pressurize the canister(s) with humid zero air to approximately 206 kPa (-30 psig). If a zero gas
generator system is used, the flow rate may need to be limited to maintain the zero air quality.
11.1.5 The zero shut-offvalve is closed and the canister(s) is allowed to vent down to atmospheric pressure
through the vent shut-off valve. The vent shut-off valve is closed. Repeat Sections 11.1.3 through 11.1.5 two
additional times for a total of three (3) evacuation/pressurization cycles for each set of canisters.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-25
-------
Method TO-14A
VOCs
11.1.6 At the end of the evacuation/pressurization cycle, the canister is pressurized to 206 kPa (30 psig) with
humid zero air. The canister is then analyzed by a GC/MS or GC/FID/ECD analytical system. Any canister that
has not tested clean (compared to direct analysis of humidified zero air of <0.2 ppbv of targeted VOCs) should
not be used. As a "blank" check of the canister(s) and cleanup procedure, the final humid zero air fill of 100%
of the canisters is analyzed until the cleanup system and canisters are proven reliable (<0.2 ppbv of targeted
VOCs). The check can then be reduced to a lower percentage of canisters.
11.1.7 The canister is reattached to the cleaning manifold and is then reevacuated to <0.05 mm Hg and
remains in this condition until used. The canister valve is closed. The canister is removed from the cleaning
system and the canister connection is capped with a stainless steel fitting. The canister is now ready for collection
of an air sample. An identification tag is attached to the neck of each canister for field notes and chain-of-custody
purposes.
11.1.8 As an option to the humid zero air cleaning procedures, the canisters could be heated in an isothermal
oven to 1000 C during the procedure described in Section 11.1.3 to assist in removing less volatile VOCs from
the walls of the canister.
[Note: Do not heat the values of the canister during this sequence.]
Once heated, the canisters are evacuated to 0.05 mm Hg. At the end of the heated/evacuated cycle, the canisters
are pressurized with humid zero air and analyzed by the GC/FID/ECD system. Any canister that has not tested
clean (<0.2 ppbv of targeted compounds) should not be used. Once tested clean, the canisters are reevacuated
to 0.05 mm Hg and remain in the evacuated state until used.
11.2 Sampling System Cleaning and Certification
11.2.1 Cleaning Sampling System Components
11.2.1.1 Sample components are disassembled and cleaned before the sampler is assembled. Nonmetallic
parts are rinsed with HPLC grade deionized water and dried in a vacuum oven at 50°C. Typically, stainless steel
parts and fittings are cleaned by placing them in a beaker of methanol in an ultrasonic bath for 15 minutes. This
procedure is repeated with hexane as the solvent.
11.2.1.2 The parts are then rinsed with HPLC grade deionized water and dried in a vacuum oven at 100°C
for 12 to 24 hours.
11.2.1.3 Once the sampler is assembled, the entire system is purged with humid zero air for 24 hours.
11.2.2 Humid Zero Air Certification
[Note: In the following sections, "certification " is defined as evaluating the sampling system with humid zero
air and humid calibration gases that pass through all active components of the sampling system. The system
is "certified" if no significant additions or deletions (<0.2 ppbv of targeted compounds) have occurred when
challenged with the test gas stream.]
11.2.2.1 The cleanliness of the sampling system is determined by testing the sampler with humid zero air
without an evacuated gas cylinder, as follows.
11.2.2.2 The calibration system and manifold are assembled, as illustrated in Figure 8. The sampler
(without an evacuated gas cylinder) is connected to the manifold and the zero air cylinder activated to generate
a humid gas stream (~2 L/min) to the calibration manifold [see Figure 8(b)].
11.2.2.3 The humid zero gas stream passes through the calibration manifold, through the sampling system
(without an evacuated canister) to a GC/FID/ECD analytical system at 75 mL/min so that 35 mL/min is pulled
Page 14A-26
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
through the six-port valve and routed through the cryogenic trap (see Section 10.2.2.1) at the appropriate time
while the extra sample is vented.
[Note: The exit of the sampling system (without the canister) replaces the canister in Figure 4. ]
After the sample (-400 mL) is preconcentrated on the trap, the trap is heated and the VOCs are thermally
desorbed onto the head of the capillary column. Since the column is at -50°C, the VOCs are cryofocussed on the
column. Then, the oven temperature (programmed) increases and the VOCs begin to elute and are detected by
a GC/MS (see Section 10.2) or the GC/FID/ECD (see Section 10.3). The analytical system should not detect
greater than 0.2 ppbv of targeted VOCs in order for the sampling system to pass the humid zero air certification
test. Chromatograms of a certified sampler and contaminated sampler are illustrated in Figures 17(a) and (b),
respectively. If the sampler passes the humid zero air test, it is then tested with humid calibration gas standards
containing selected VOCs at concentration levels expected in field sampling (e.g., -0.5 to 2 ppbv) as outlined
in Section 11.2.3.
11.2.3 Sampler System Certification with Humid Calibration Gas Standards.
11.2.3.1 Assemble the dynamic calibration system and manifold as illustrated in Figure 8.
11.2.3.2 Verify that the calibration system is clean (less than 0.2 ppbv of targeted compounds) by
sampling a humidified gas stream, without gas calibration standards, with a previously certified clean canister
(see Section 12.1).
11.2.3.3 The assembled dynamic calibration system is certified clean if <0.2 ppbv of targeted compounds
are found.
11.2.3.4 For generating the humidified calibration standards, the calibration gas cylinder(s) (see Section
8.2) containing nominal concentrations of 10 ppmv in nitrogen of selected VOCs, are attached to the calibration
system, as outlined in Section 10.2.3.1. The gas cylinders are opened and the gas mixtures are passed through
0 to 10 mL/min certified mass flow controllers and blended with humidified zero air to generate ppbv levels of
calibration standards.
11.2.3.5 After the appropriate equilibrium period, attach the sampling system (containing a certified
evacuated canister) to the manifold, as illustrated in Figure 8(a).
11.2.3.6 Sample the dynamic calibration gas stream with the sampling system according to Section 9.2.1.
[Note: To conserve generated calibration gas, bypass the canister sampling system manifold and attach the
sampling system to the calibration gas stream at the inlet of the in-line filter of the sampling system so the flow
will be less than 500 mL/min.]
11.2.3.7 Concurrent with the sampling system operation, realtime monitoring of the calibration gas stream
is accomplished by the on-line GC/MS or GC-multidetector analytical system [Figure 8(b)] to provide reference
concentrations of generated VOCs.
11.2.3.8 At the end of the sampling period (normally same time period used for anticipated sampling), the
sampling system canister is analyzed and compared to the reference GC/MS or GC-multi-detector analytical
system to determine if the concentration of the targeted VOCs was increased or decreased by the sampling
system.
11.2.3.9 A recovery of between 90% and 110% is expected for all targeted VOCs.
12. Performance Criteria and Quality Assurance
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-27
-------
Method TO-14A
VOCs
12.1 Standard Operating Procedures (SOPs)
12.1.1 SOPs should be generated in each laboratory describing and documenting the following activities:
(1) assembly, calibration, leak check, and operation of specific sampling systems and equipment used; (2)
preparation, storage, shipment, and handling of samples; (3) assembly, leak-check, calibration, and operation of
the analytical system, addressing the specific equipment used; (4) canister storage and cleaning; and (5) all
aspects of data recording and processing, including lists of computer hardware and software used.
12.1.2 Specific stepwise instructions should be provided in the SOPs and should be readily available to and
understood by the laboratory personnel conducting the work.
12.2 Method Relative Accuracy and Linearity
12.2.1 Accuracy can be determined by injecting VOC standards (see Section 8.2) from an audit cylinder into
a sampler. The contents are then analyzed for the components contained in the audit canister. Percent relative
accuracy is calculated:
X - V
% Relative Accuracy = ——— x 100
where:
Y = concentration of the targeted compound recovered from sampler, ppbv.
X = concentration of VOC targeted compounds in the NIST-SRM audit cylinders, ppbv.
12.2.2 If the relative accuracy does not fall between 90 and 110 percent, the field sampler should be removed
from use, cleaned, and recertified according to initial certification procedures outlined in Sections 11.2.2 and
11.2.3. Historically, concentrations of carbon tetrachloride, tetrachloroethylene, and hexachlorobutadiene have
sometimes been detected at lower concentrations when using parallel ECD and FID detectors. When these three
compounds are present at concentrations close to calibration levels, both detectors usually agree on the reported
concentrations. At concentrations below 4 ppbv, there is a problem with nonlinearity of the ECD. Plots of
concentration versus peak area for calibration compounds detected by the ECD have shown that the curves are
nonlinear for carbon tetrachloride, tetrachloroethylene, and hexachlorobutadiene, as illustrated in Figures 18(a)
through 18(c). Other targeted ECD and FID compounds scaled linearly for the range 0 to 8 ppbv, as shown for
chloroform in Figure 18(d). For compounds that are not linear over the calibration range, area counts generally
roll off between 3 and 4 ppbv. To correct for the nonlinearity of these compounds, an additional calibration step
is performed. An evacuated stainless steel canister is pressurized with calibration gas a nominal concentration
of 8 ppbv. The sample is then diluted to approximately 3.5 ppbv with zero air and analyzed. The instrument
response factor (ppbv/area) of the ECD for each of the three compounds is calculated for the 3.5 ppbv sample.
Then, both the 3.5 ppbv and the 8 ppbv response factors are entered into the ECD calibration table. Most
commercial analytical systems have software designed to accommodate multilevel calibration entries, so the
correct response factors are automatically calculated for concentrations in this range.
12.3 Method Modification
12.3.1 Sampling
12.3.1.1 The sampling system for pressurized canister sampling could be modified to use a lighter, more
compact pump. The pump currently being used weights about 16 kilograms (~35 lbs). Commercially available
pumps that could be used as alternatives to the prescribed sampler pump are described below. Metal Bellow MB-
Page 14A-28
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
41 pump: These pumps are cleaned at the factory; however, some precaution should be taken with the circular
(-4.8 cm diameter) Teflon® and stainless steel part directly under the flange. It is often dirty when received and
should be cleaned before use. This part is cleaned by removing it from the pump, manually cleaning with
deionized water, and placing in a vacuum oven at 100°C for at least 12 hours. Exposed parts of the pump head
are also cleaned with swabs and allowed to air dry. These pumps have proven to be very reliable; however, they
are only useful up to an outlet pressure of about 137 kPa (-20 psig). Neuberger Pump: Viton gaskets or seals
must be specified with this pump. The "factory direct" pump is received contaminated and leaky. The pump is
cleaned by disassembling the pump head (which consists of three stainless steel parts and two gaskets), cleaning
the gaskets with deionized water and drying in a vacuum oven, and remachining (or manually lapping) the sealing
surfaces of the stainless steel parts. The stainless steel parts are then cleaned with methanol, hexane, deionized
water and heated in a vacuum oven. The cause for most of the problems with this pump has been scratches on
the metal parts of the pump head. Once this rework procedure is performed, the pump is considered clean and
can be used up to about 240 kPa (-35 psig) output pressure. This pump is utilized in the sampling system
illustrated in Figure 3.
12.3.1.2 Alternative Sampler Configuration. The sampling system described in Compendium
Method TO-14A can be modified as described in Appendix C (see Figure C-l). Originally, this configuration
was used in EPA's FY-88 Urban Air Toxics Pollutant Program.
12.3.2 Analysis.
12.3.2.1 Inlet tubing from the calibration manifold could be heated to 50°C (same temperature as the
calibration manifold) to prevent condensation on the internal walls of the system.
12.3.2.2 The analytical strategy for Method TO-14A involves positive identification and quantitation by
GC/MS/SCAN/SIM mode of operation with optional FID. This is a highly specific and sensitive detection
technique. Because a specific detector system (GC/MS/SCAN/SIM) is more complicated and expensive than
the use of non-specific detectors (GC/FID/ECD/PID), the analyst may want to perform a screening analysis and
preliminary quantitation of VOC species in the sample, including any polar compounds, by utilizing the GC-
multidetector (GC/FID/ECD/PID) analytical system prior to GC/MS analysis. This system can be used for
approximate quantitation. The GC/FID/ECD/PID provides a "snap-shot" of the constituents in the sample,
allowing the analyst to determine:
- Extent of misidentification due to overlapping peaks.
- Whether the constituents are within the calibration range of the anticipated GC/MS/SCAN/SIM
analysis or does the sample require further dilution.
- Are there unexpected peaks which need further identification through GC/MS/SCAN or are there peaks
of interest needing attention?
If unusual peaks are observed from the GC/FID/ECD/PID system, the analyst then performs a GC/MS/SCAN
analysis. The GC/MS/SCAN will provide positive identification of suspect peaks from the GC/FID/ECD/PID
system. If no unusual peaks are identified and only a select number of VOCs are of concern, the analyst can then
proceed to GC/MS/SIM. The GC/MS/SIM is used for final quantitation of selected VOCs. Polar compounds,
however, cannot be identified by the GC/MS/SIM due to the use of a Nafion® dryer to remove water from the
sample prior to analysis. The dryer removes polar compounds along with the water. The analyst often has to
make this decision incorporating project objectives, detection limits, equipment availability, cost and personnel
capability in developing an analytical strategy. The use of the GC/FID/ECD/PID as a "screening" approach, with
the GC/MS/SCAN/SIM for final identification and quantitation, is outlined in Figure 20.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-29
-------
Method TO-14A
VOCs
12.4 Method Safety
This procedure may involve hazardous materials, operations, and equipment. This method does not purport to
address all of the safety problems associated with its use. It is the user's responsibility to establish appropriate
safety and health practices and determine the applicability of regulatory limitation prior to the implementation
of this procedure. This should be part of the user's SOP manual.
12.5 Quality Assurance (see Figure 21)
12.5.1 Sampling System
12.5.1.1 Section 9.2 suggests that a portable GC system be used as a "screening analysis" prior to
locating fixed-site samplers (pressurized or subatmospheric).
12.5.1.2 Section 9.2 requires pre and post-sampling measurements with a certified mass flow
controller for flow verification of sampling system.
12.5.1.3 Section 11.1 requires all canisters to be pressure tested to 207 kPa ± 14 kPa (30 psig ± 2
psig) over a period of 24 hours.
12.5.1.4 Section 11.1 requires that all canisters be certified clean (<0.2 ppbv of targeted VOCs)
through a humid zero air certification program.
12.5.1.5 Section 11.2.2 requires all field sampling systems to be certified initially clean (<0.2 ppbv
of targeted VOCs) through a humid zero air certification program.
12.5.1.6 Section 11.2.3 requires all field sampling systems to pass an initial humidified calibration
gas certification [at VOC concentration levels expected in the field (e.g., 0.5 to 2 ppbv)] with a percent recovery
of greater than 90.
12.5.2 GC/MS/SCAN/SIM System Performance Criteria
12.5.2.1 Section 10.2.1 requires the GC/MS analytical system to be certified clean (<0.2 ppbv of
targeted VOCs) prior to sample analysis, through a humid zero air certification.
12.5.2.2 Section 10.2.2 requires the daily tuning of the GC/MS with 4-BFB and that it meet the key
ions and ion abundance criteria (10%) outlined in Table 5.
12.5.2.3 Section 10.2.3 requires both an initial multipoint humid static calibration (three levels plus
humid zero air) and a daily calibration (one point) of the GC/MS analytical system.
12.5.3 GC-Multidetector System Performance Criteria
12.5.3.1 Section 10.3.1 requires the GC/FID/ECD analytical system, prior to analysis, to be certified
clean (<0.2 ppbv of targeted VOCs) through a humid zero air certification.
12.5.3.2 Section 10.3.2 requires that the GC/FID/ECD analytical system establish retention time
windows for each analyte prior to sample analysis, when a new GC column is installed, or major components of
the GC system altered since the previous determination.
12.5.3.3 Section 8.2 requires that all calibration gases be traceable to NIST-SRMs.
12.5.3.4 Section 10.3.2 requires that the retention time window be established throughout the course
of a 72-hr analytical period.
12.5.3.5 Section 10.3.3 requires both an initial multipoint calibration (three levels plus humid zero
air) and a daily calibration (one point) of the GC/FID/ECD analytical system with zero gas dilution of NIST
traceable gases.
Page 14A-30
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
13. Acknowledgements
The determination of VOCs in ambient air is a complex task, primarily because of the wide variety of compounds
of interest and the lack of standardized sampling and analytical procedures. While there are numerous procedures
for sampling and analyzing VOCs in ambient air, this method draws upon the best aspects of each one and
combines them into a standardized methodology. In many cases, the individuals listed in the acknowledgement
table contributed to the research, documentation and peer review of the original Compendium Method TO-14 and
now revised as Compendium Method TO-14A. In some cases, new names appear as likely sources of new
information.
14. References
1. Oliver, K. D., Pleil, J. D., and McClenny, W. A. "Sample Integrity of Trace Level Volatile Organic
Compounds in Ambient Air Stored in Specially Prepared Polished Canisters," Atmos. Environ. 20:1403, 1986.
2. Holdren, M. W. and Smith, D. L. "Stability of Volatile Organic Compounds While Stored in Specially
Prepared Polished Stainless Steel Canisters," U. S. Environmental Protection Agency, Research Triangle Park,
NC, Final Report, EPA Contract No. 68-02-4127, Battelle, January 1986.
3. Kelly, T. J. and Holdren, M. W., "Applicability of Canisters for Sample Storage in the Determination of
Hazardous Air Pollutants," Atmos. Environ., 29(19):2595, 1995.
4. McClenny, W. A., Pleil, J. D., Evans, G. F., Oliver, K. D., Holdren, M. W., and Winberry, W. T., "Canister-
Based Method for Monitoring Toxic VOCs in Ambient Air," JAWMA, 41(10): 1038, 1991.
5. McClenny, W. A., Pleil, J. D., Holdren, J. W., and Smith, R. N. "Automated Cryogenic Preconcentration and
Gas Chromatographic Determination of Volatile Organic Compounds," Anal. Chem. 56:2947, 1984.
6. Pleil, J. D., Oliver, K. D., and McClenny, W. A., "Enhanced Performance of Nafion® Dryers in Removing
Water from Samples Prior to Gas Chromatographic Analysis," JAPCA, 37:244, 1987.
7. Oliver, K. D. and Pleil, J. D., "Automated Cryogenic Sampling and Gas Chromatographic Analysis of
Ambient Vapor-Phase Organic Compounds: Procedures and Comparison Tests," ManTech, Inc. - Environmental
Services, EPA Contract No. 68-02-4035, U. S. Environmental Protection Agency, Research Triangle Park, NC,
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-31
-------
Method TO-14A
VOCs
COMPENDIUM METHOD TO-14A ACKNOWLEDGEMENT
Topic
Sampling System
Analytical System
GC/FID,
GC/FID/ECD
GC/FID,
GC/FID/ECD/PID
GC/MS/SCAN/SIM
Canister Cleaning
Certification and
VOC Canister Storage
Stability
Cryogenic
Sampling Unit
Contact
Mr. Frank McElroy
Dr. Bill McClenny
Mr. Joachim Pleil
Mr. Bill Taylor
Mr. Joseph P. Krasnec
Dr. Bill McClenny
Mr. Joachim Pleil
Ms. Karen D. Oliver
Mr. Dave-Paul Dayton
Ms. JoAnn Rice
Dr. Bill McClenny
Mr. Joachim Pleil
Dr. Bill McClenny
Mr. Joachim Pleil
Mr. Dave-Paul Dayton
Ms. JoAnn Rice
Dr. R.K.M. Jayanty
Dr. Bill McClenny
Mr. Joachim Pleil
U.S. EPA Mr. Howard Christ
Audit Gas Standards
Address
U.S. Environmental Protection Agency
National Exposure Research Laboratory
MD-77
Research Triangle Park, NC 27711
U.S. Environmental Protection Agency
National Exposure Research Laboratory
MD-44
Research Triangle Park, NC 27711
Graseby
500 Technology Ct.
Smyrna, GA 30082
Scientific Instrumentation Specialists, Inc.
P.O. Box 8941
Moscow, Idaho 83843
U.S. Environmental Protection Agency
National Exposure Research Laboratory
MD-44
Research Triangle Park, NC 27711
ManTech, Inc.
Environmental Sciences
P.O. Box 12313
Research Triangle Park, NC 27709
ERG
P.O. Box 13000
Progress Center
Research Triangle Park, NC 27709
U.S. Environmental Protection Agency
National Exposure Research Laboratory
MD-44
Research Triangle Park, NC 27711
U.S. Environmental Protection Agency
National Exposure Research Laboratory
MD-44
Research Triangle Park, NC 27711
ERG
P.O. Box 13000
Progress Center
Research Triangle Park, NC 27709
Research Triangle Institute
P.O. Box 12194
Research Triangle Park, NC 27709
U.S. Environmental Protection Agency
National Exposure Research Laboratory
MD-44
Research Triangle Park, NC 27711
U.S. Environmental Protection Agency
National Exposure Research Laboratory
MD-77B
Research Triangle Park, NC 27711
Telephone No.
919-541-2622
919-541-3158
919-541-4680
1-800-241-6898
208-882-3860
919-541-3158
919-541-4680
919-549-0611
919-481-0212
919-541-3158
919-541-4680
919-541-3158
919-541-4680
919-481-0212
919-541-6000
919-541-3158
919-541-4680
919-541-4531
Page 14A-32
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
1985.
8. McClenny, W. A. and Pleil, J. D., "Automated Calibration and Analysis of VOCs with a Capillary Column
Gas Chromatograph Equipped for Reduced Temperature Trapping," in Proceedings of the 1984 Air Pollution
Control Association Annual Meeting, San Francisco, CA, June 24-29, 1984.
9. McClenny, W. A., Pleil, J. D., Lumpkin, T. A., and Oliver, K. D., "Update on Canister-Based Samplers for
VOCs," in Proceedings of the 1987 EPA/APCA Symposium on Measurement of Toxic and Related Air
Pollutants, May 1987.
10. Pleil, J. D., "Automated Cryogenic Sampling and Gas Chromatographic Analysis of Ambient Vapor-Phase
Organic Compounds: System Design," ManTech, Inc. - Environmental Services, U. S. Environmental Protection
Agency, Research Triangle Park, NC, 1982, EPA Contract No. 68-02-2566.
11. Oliver, K. D. and Pleil, J. D., "Analysis of Canister Samples Collected During the CARB Study in August
1986," U. S. Environmental Protection Agency, Research Triangle Park, NC, ManTech, Inc. - Environmental
Services, 1987.
12. Pleil, J. D., and Oliver, K. D., "Measurement of Concentration Variability of Volatile Organic Compounds
in Indoor Air: Automated Operation of a Sequential Syringe Sampler and Subsequent GC/MS Analysis," U. S.
Environmental Protection Agency, Research Triangle Park, NC, ManTech, Inc. - Environmental Services, 1987.
13. Walling, J. F., "The Utility of Distributed Air Volume Sets When Sampling Ambient Air Using Solid
Adsorbents," Atmos. Environ., 18:855-859, 1984.
14. Walling, J. F., Bumgarner, J. E., Driscoll, J. D., Morris, C. M., Riley, A. E. and Wright, L. H., "Apparent
Reaction Products Desorbed From Tenax Used to Sample Ambient Air," Atmos. Environ., 20:51-57, 1986.
15. Berkley, R E., "Overview of Field Deployable Gas Chromatographic Analyzers of Airborne Toxic Organic
Vapors," Proceedings of the 1994 On-Site Analysis Conference, Houston, TX, January 24-26, 1994.
16. McElroy, F. F., Thompson, V. L., Holland, D. M., Lonneman, W. A., and Seila, R. L., "Cryogenic
Preconcentration-Direct FID Method for Measurement of Ambient NMOC: Refinement and Comparison with
GC Speciation," JAPCA, 35(6):710, 1986.
17. Rasmussen, R. A. and Lovelock, J. E., "Atmospheric Measurements Using Canister Technology," J.
Geophys. Res., 83:8369-8378, 1983.
18. Rasmussen, R. A. and Khalil, M. A. K., "Atmospheric Halocarbons: Measurements and Analysis of Selected
Trace Gases," in I'roc. NATO ASI on Atmospheric Ozone, BO: 209-231.
19. Dayton, D. D. and Rice, J., Development and Evaluation of a Prototype Analytical System for Measuring
Air Toxics, U. S. Environmental Protection Agency, Research Triangle Park, NC 27711, EPA Contract No. 68-
02-3889, WA No. 120, November 1987.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-33
-------
Method TO-14A
VOCs
TABLE 1. COMPENDIUM METHOD TO-14A VOC TCL DATA SHEET
COMPOINI) (SYNONYM)
I'ORMl I.A
MOI.KCU.AR
\\ ] :icii 11
BOILING
POINT i C 1
MUTING
POINT ( C >
CAS NO.
Freon 12 (Dichlorodifluoromethane)
C12CF2
120.91
-29.8
-158.0
75-71-8
Methyl chloride (Chloromethane)
CH3C1
50.49
-24.2
-97.1
74-87-3
Freon 114 (1,2-Dichloro-l,1,2,2-
tetrafluoroethane)
C1CF2CC1F2
170.93
4.1
-94.0
76-14-2
Vinyl chloride (Chloroethylene)
ch2=chci
62.50
-13.4
-1538.0
75-01-4
Methyl bromide (Bromomethane)
CH3Br
94.94
3.6
-93.6
74-83-9
Ethyl chloride (Chloroethane)
CH3CH2C1
64.52
12.3
-136.4
75-00-3
Freon 11 (Trichlorofluoromethane)
CCI3F
137.38
23.7
-111.0
75-69-4
Vinylidene chloride (1,1-Dichloroethene)
C2H2C12
96.95
31.7
-122.5
75-35-4
Dichloromethane (Methylene chloride)
ch2ci2
84.94
39.8
-95.1
75-09-2
Freon 113 (l,l,2-Trichloro-l,2,2-
trifluoroethane)
cf2cicci2f
187.38
47.7
-36.4
76-13-1
1,1-Dichloroethane (Ethylidene chloride)
ch3chci2
98.96
57.3
-97.0
74-34-3
cis-l,2-Dichloroethylene
CHC1=CHC1
96.94
60.3
-80.5
156-59-2
Chloroform (Trichloromethane)
CHC13
119.38
61.7
-63.5
67-66-3
1,2-Dichloroethane (Ethylene dichloride)
C1CH2CH2C1
98.96
83.5
-35.3
107-06-2
Methyl chloroform (1,1,1-Trichloroethane)
CH3CC13
133.41
74.1
-30.4
71-55-6
Benzene (Cyclohexatriene)
c6H6
78.12
80.1
5.5
71-43-2
Carbon tetrachloride (Tetrachloromethane)
CC14
153.82
76.5
-23.0
56-23-5
1,2-Dichloropropane (Propylene dichloride)
CH3CHC1CH2C1
112.99
96.4
-100.4
78-87-5
Trichloroethylene (Trichloroethene)
cich=cci2
131.29
87
-73.0
79-01-6
cis-l,3-Dichloropropene (cis-1,3-
dichloropropylene)
ch3cci=chci
110.97
104.3
—
542-75-6
trans-1,3-Dichloropropene (trans-1,3-
Dichloropropylene)
cich2ch=chci
110.97
112.0
—
542-75-6
1,1,2-Trichloroethane (Vinyl trichloride)
ch2cichci2
133.41
113.8
-36.5
79-00-5
Toluene (Methyl benzene)
c6h5ch3
92.15
110.6
-95.0
108-88-3
1,2-Dibromoethane (Ethylene dibromide)
BrCH2CH2Br
187.88
131.3
9.8
106-93-4
Tetrachloroethylene (Perchloroethylene)
C12C=CC12
165.83
121.1
-19.0
127-18-4
Chlorobenzene (Phenyl chloride)
c6H5ci
112.56
132.0
-45.6
108-90-7
Ethylbenzene
c6h5c2h5
106.17
136.2
-95.0
100-41-4
m-Xylene (1,3-Dimethylbenzene)
1,3-(CH3)2C6H4
106.17
139.1
-47.9
108-38-3
p-Xylene (,14-Dimethylxylene)
1,4-(CH3)2C6H4
106.17
138.3
13.3
106-42-3
Styrene (Vinyl benzene)
c6h5ch=ch2
104.16
145.2
-30.6
100-42-5
1,1,2,2-Tetrachloroethane
chci2chci2
167.85
146.2
-36.0
79-34-5
o-Xylene (1,2-Dimethylbenzene)
1,2-(CH3)2C6H4
106.17
144.4
-25.2
95-47-6
1,3,5-Trimethylbenzene (Mesitylene)
1,3,5-(CH3)3C6H6
120.20
164.7
-44.7
108-67-8
1,2,4-Trimethylbenzene (Pseudocumene)
1,2,4-(CH3)3C6H6
120.20
169.3
-43.8
95-63-6
m-Dichlorobenzene (1,3-Dichlorobenzene)
1,3-C12C6H4
147.01
173.0
-24.7
541-73-1
Benzyl chloride (a-Chlorotoluene)
c6h5ch2ci
126.59
179.3
-39.0
100-44-7
o-Dichlorobenzene (1,2-dichlorobenzene)
1,2-C12C6H4
147.01
180.5
-17.0
95-50-1
p-Dichlorobenzene (1,4-dichlorobenzene)
1,4-C12C6H4
147.01
174.0
53.1
106-46-7
1,2,4-Trichlorobenzene
1,2,4-C13C6H3
181.45
213.5
17.0
120-82-1
Hexachlorobutadiene (1,1,2,3,4,4-Hexachloro-
1,3-butadiene)
C4C16
260.8
186
(sublimes)
-21.0
87-68-3
Page 14A-34
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
TABLE 2. ION/ABUNDANCE AND EXPECTED RETENTION TIME FOR SELECTED
COMPENDIUM METHOD TO-14A VOCs ANALYZED BY GC/MS/SIM
Ion/Abundance
I Apected Retention
COMPOUND (SYNONYM)
(amu/% base peak)
Time (min)
Freon 12 (Dichlorodifluoromethane)
85/100
5.01
87/31
Methyl chloride (Chloromethane)
50/100
5.69
52/34
Freon 114 (l,2-Dichloro-l,l,2,2-tetrafluoroethane)
85/100
6.55
135/56
87/33
Vinyl chloride (Chloroethene)
62/100
6.71
27/125
64/32
Methyl bromide (Bromomethane)
94/100
7.83
96/85
Ethyl chloride (Chloroethane)
64/100
8.43
29/140
27/140
Freon 11 (Trichlorofluoromethane)
101/100
9.97
103/67
Vinylidene chloride (1,1-Dichloroethene)
61/100
10.93
96/55
63/31
Dichloromethane (Methylene chloride)
49/100
11.21
84/65
86/45
Freon 113 (l,l,2-Trichloro-l,2,2-trifluoroethane)
151/100
11.60
101/140
103/90
1,1 -Dichloroethane (Ethylidene chloride)
63/100
12.50
27/64
65/33
cis-1,2-Dichloroethy lene
61/100
13.40
96/60
98/44
Chloroform (Trichloromethane)
83/100
13.75
85/65
47/35
1,2-Dichloroethane (Ethylene dichloride)
62/100
14.39
27/70
64/31
Methyl chloroform (1,1,1-Trichloroethane)
97/100
14.62
99/64
61/61
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-35
-------
Method TO-14A
VOCs
TABLE 2. (continued)
Ion/Abundance
I Apected Retention
COMPOUND (SYNONYM)
(anui/% base peak)
l ime (min)
Benzene (Cyclohexatriene)
78/100
15.04
77/25
50/35
Carbon tetrachloride (Tetrachloromethane)
117/100
15.18
119/97
1,2-Dichloropropane (Propylene dichloride)
63/100
15.83
41/90
62/70
Trichloroethy lene (Trichloroethene)
130/100
16.10
132/92
95/87
cis-1,3 -Dichloropropene
75/100
16.96
39/70
77/30
trans-l,3-Dichloropropene (cis-1,3 Dichloropropylene)
75/100
17.49
39/70
77/30
1,1,2-Trichloroethane (Vinyl trichloride)
97/100
17.61
83/90
61/82
Toluene (Methyl benzene)
91/100
17.86
92/57
1,2-Dibromoethane (Ethylene dibromide)
107/100
18.48
109/96
27/115
Tetrachloroethylene (Perchloroethylene)
166/100
19.01
164/74
131/60
Chlorobenzene (Phenyl chloride)
112/100
19.73
77/62
114/32
Ethylbenzene
91/100
20.20
106/28
m,p-Xylene (1,3/1,4-Dimethylbenzene)
91/100
20.41
106/40
Styrene (Vinyl benzene)
104/100
20.81
78/60
103/49
1,1,2,2-Tetrachloroethane (Tetrachlorethane)
83/100
20.92
85/64
o-Xylene (1,2-Dimethylbenzene)
91/100
20.92
106/40
4-Ethyltoluene
105/100
22.53
120/29
Page 14A-36
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
TABLE 2. (continued)
COMPOUND (SYNONYM)
Inn/Abundance
(anui/% base peak)
I Apeeted Retention
l ime (min)
1,3,5-Trimethylbenzene (Mesitylene)
105/100
22.65
120/42
1,2,4-Trimethylbenzene (Pseudocumene)
105/100
23.18
120/42
m-Dichlorobenzene (1,3 -Dichlorobenzene)
146/100
23.31
148/65
111/40
Benzyl chloride (a-Chlorotoluene)
91/100
23.32
126/26
p-Dichlorobenzene (1,4-diehlorobenzene)
146/100
23.41
148/65
111/40
o-Dichlorobenzene (1,2-diehlorobenzene)
146/100
23.88
148/65
111/40
1,2,4-Triehlorobenzene
180/100
26.71
182/98
184/30
Hexachlorobutadiene (1,1,2,3,4,4 Hexachloro-1,3-butadiene)
225/100
27.68
227/66
223/60
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-37
-------
Method TO-14A
VOCs
TABLE 3. GENERAL GC AND MS OPERATING CONDITIONS FOR
COMPENDIUM METHOD TO-14A
Chromatography
Column
General OV-1 crosslinked methyl silicone (50-m x 0.31-mm I.D., 17 um
film thickness), or equivalent
Carrier Gas
Helium (~2.0 mL/min at 250°C)
Injection Volume
Constant (1-3 |iL)
Injection Mode
Splitless
Temperature Program
Initial Column Temperature
-50°C
Initial Hold Time
2 min
Program
8°C/min to 150°C
Final Hold Time
15 min
Mass Spectrometer
Mass Range
18 to 250 amu
Scan Time
1 sec/scan
EI Condition
70 eV
Mass Scan
Follow manufacturer's instruction for selecting mass selective detector
(MS) and selected ion monitoring (SIM) mode
Detector Mode
Multiple ion detection
FID Svstem (Optional)
Hydrogen Flow
~30 mL/minute
Carrier Flow
~30 mL/minute
Burner Air
-400 mL/minute
Page 14A-38
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
TABLE 4. 4-BFB KEY IONS AND ION ABUNDANCE CRITERIA
Mass
Ion Abundance Criteria
50
15 to 40% of mass 95
75
30 to 60% of mass 95
95
Base Peak, 100% Relative Abundance
96
5 to 9% of mass 95
173
<2% of mass 174
174
>50% of mass 95
175
5 to 9% of mass 174
176
>95%but< 101% of mass 174
177
5 to 9% of mass 176
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-39
-------
Method TO-14A
VOCs
TABLE 5. COMPENDIUM METHOD TO-14A RESPONSE FACTORS
(ppbv/area count) AND EXPECTED RETENTION TIME FOR
GC/MS/SIM ANALYTICAL CONFIGURATION
Compounds
Response Factor
(ppbv/area count)
I 'Apecled Retention
1 ime (minutes)
Freon 12
0.6705
5.01
Methyl chloride
4.093
5.64
Freon 114
0.4928
6.55
Vinyl chloride
2.343
6.71
Methyl bromide
2.647
7.83
Ethyl chloride
2.954
8.43
Freon 11
0.5145
9.87
Vinylidene chloride
1.037
10.93
Dichloromethane
2.255
11.21
T richlorotrifluoroethane
0.9031
11.60
1,1 -Dichloroethane
1.273
12.50
cis-1,2-Dichloroethylene
1.363
13.40
Chloroform
0.7911
13.75
1,2-Dichloroethane
1.017
14.39
Methyl chloroform
0.7078
14.62
Benzene
1.236
15.04
Carbon tetrachloride
0.5880
15.18
1,2-Dichloropropane
2.400
15.83
T richloroethy lene
1.383
16.10
cis-1,3-Dichloropropene
1.877
16.96
trans-1,3 -Dichloropropene
1.338
17.49
1.1,2-Trichloroethane
1.891
17.61
Toluene
0.9406
17.86
1,2-Dibromoethane (EDB)
0.8662
18.48
T etrachloroethy lene
0.7357
19.01
Chlorobenzene
0.8558
19.73
Ethylbenzene
0.6243
20.20
m,p-Xylene
0.7367
20.41
Styrene
1.888
20.80
1,1,2,2-T etrachloroethane
1.035
20.92
o-Xylene
0.7498
20.92
4-Ethyltoluene
0.6181
22.53
1,3,5-Trimethylbenzene
0.7088
22.65
1,2,4-T rimethylbenzene
0.7536
23.18
m-Dichlorobenzene
0.9643
23.31
Benzyl chloride
1.420
23.32
p-Dichlorobenzene
0.8912
23.41
o-Dichlorobenzene
1.004
23.88
1,2,4-Trichlorobenzene
2.150
26.71
Hexachlorobutadiene
0.4117
27.68
Page 14A-40
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
TABLE 6. COMPENDIUM METHOD TO-14A
GC/MS/SIM CALIBRATION TABLE
*** External Standard ***
Operator: JDP
Sample Info: SYR 1
Misc Info:
Integration File Name: DATA:SYR2A02A.I
8 Jan 97 10:02 am
Sequence Index: 1
Last Update
Reference Peak Window
Non-Reference Peak Window
Bottle Number: 2
8 Jan 87 8:13 am
5.00 Absolute Minutes
0.40 Absolute Minutes
Sample Am
ount:
0.000 Uncalibr
ated Peak RF: 0.000
Multip
ier: 1.667
Peak
No.
'I'vpe
I ill Tvpe
Ret Time
Si<_
nal Description
Compound Name
Area
Amount
1
1
PP
5.020
Mass
85.00 amu
FREON 12
12893
4011
pptv
2
1
PP
5.654
Mass
50.00 amu
METHYLCHLORI
4445
2586
pptv
3
1
BP
6.525
Mass
85.00 amu
FREON 114
7067
1215
pptv
4
1
PB
6.650
Mass
62.00 amu
VINYLCHLORID
2892
1929
pptv
5
1
BP
7.818
Mass
94.00 amu
METHYLBROMID
2401
1729
pptv
6
1
BB
8.421
Mass
64.00 amu
ETHYLCHLORID
2134
2769
pptv
7
1
BV
9.940
Mass
101.00 amu
FREON 11
25069
6460
pptv
8
1
BP
10.869
Mass
61.00 amu
VINDENECHLOR
5034
1700
pptv
9
1
BP
11.187
Mass
49.00 amu
DICHLOROMETH
4803
2348
pptv
10
1
PP
11.225
Mass
41.00 amu
ALLYCHLORID
761
8247
pptv
11
1
BP
11.578
Mass
151.00 amu
3CHL3FLUETHA
5477
1672
pptv
12
1
BP
12.492
Mass
63.00 amu
UDICHLOETH
5052
1738
pptv
13
1
VP
13.394
Mass
61.00 amu
c-l,2DICHLET
4761
1970
pptv
14
1
PH
13.713
Mass
83.00 amu
CHLOROFORM
5327
1678
pptv
15
1
BP
14.378
Mass
62.00 amu
1,2DICHLETHA
5009
2263
pptv
16
1
PB
14.594
Mass
97.00 amu
METHCHLOROFO
6656
2334
pptv
17
1
VP
15.009
Mass
78.00 amu
BENZENE
8352
2167
pptv
18
1
VP
15.154
Mass
117.00 amu
CARBONTETRAC
5888
1915
pptv
19
1
BB
15.821
Mass
63.00 amu
l,2DICHLPROP
3263
1799
pptv
20
1
BB
16.067
Mass
130.00 amu
TRICHLETHENE
4386
2109
pptv
21
1
PB
16.941
Mass
75.00 amu
c-l,3DICHLPR
2228
987.3
pptv
22
1
BP
17.475
Mass
75.00 amu
t-l,3DICHLPR
1626
689.2
pptv
23
1
BB
17.594
Mass
97.00 amu
U-2CHLETHA
2721
1772
pptv
24
1
BV
17.844
Mass
91.00 amu
TOLUENE
14417
2733
pptv
25
1
PB
18.463
Mass
107.00 amu
EDB
4070
1365
pptv
26
1
PH
18.989
Mass
166.00 amu
TETRACHLETHE
6874
2065
pptv
27
1
PB
19.705
Mass
112.00 amu
CHLOROBENZEN
5648
1524
pptv
28
1
BP
20.168
Mass
91.00 amu
ETHYLBENZENE
11084
1842
pptv
?Q
1
PR
?n ^7?
A/Tq«5«5
Q1 00 amu
m n.YVI T7MT7
17Q8Q
^7Q0
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-41
-------
Method TO-14A
VOCs
TABLE 6. (continued)
Peak
No.
Type
I ill Type
Ret Time
Si?4
mil Deseription
Compound Name
Area
Amount
30
1
BV
20.778
Mass
104.00 amu
STYRENE
3145
1695
pptv
31
1
BH
20.887
Mass
83.00 amu
TETRACHLETHA
4531
1376
pptv
32
1
BP
20.892
Mass
91.00 amu
o-XYLENE
9798
2010
pptv
33
1
VV
22.488
Mass
105.00 amu
4-ETHYLT OLUE
7694
1481
pptv
34
1
VB
22.609
Mass
105.00 amu
1,3,5METHBEN
6781
1705
pptv
35
1
BB
23.144
Mass
105.00 amu
1,2,4METHBEN
7892
2095
pptv
36
1
BV
23.273
Mass
146.00 amu
m-DICHLBENZE
3046
1119
pptv
37
1
VV
23.279
Mass
91.00 amu
BENZYLCHLORI
3880
1006
pptv
38
1
VB
23.378
Mass
146.00 amu
p-DICHLBENZE
6090
2164
pptv
39
1
BP
23.850
Mass
146.00 amu
o-DICHLBENZE
2896
1249
pptv
40
1
BB
26.673
Mass
180.00 amu
1,24CHLBENZ
562
767.1
pptv
41
1
BB
27.637
Mass
225.00 amu
HEXACHLBUTAD
6309
1789
pptv
Page 14A-42
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
TABLE 7. COMPENDIUM METHOD TO-14A TYPICAL RETENTION TIME (MIN) AND
CALIBRATION RESPONSE FACTORS (ppbv/area count) FOR TARGETED
VOCs ASSOCIATED WITH FID AND
ECD ANALYTICAL SYSTEM
Peak No.1
Compound
Retention Time
(RT), minutes
1II)
i;ci)
Response l actor. (Rl )
(ppbv area count)
Response f actor
(ppbv area count \ 10°)
1
Freon 12
3.65
3.465
13.89
2
Methyl chloride
4.30
0.693
3
Freon 114
5.13
0.578
22.32
4
Vinyl chloride
5.28
0.406
5
Methyl bromide
6.44
26.34
6
Ethyl chloride
7.06
0.413
7
Freon 11
8.60
6.367
1.367
8
Vinylidene chloride
9.51
0.347
9
Dichloromethane
9.84
0.903
10
Trichlorotrifluoroethane
10.22
0.374
3.955
11
1,1 -Dichloroethane
11.10
0.359
12
cis-1,2-Dichloroethylene
11.99
0.368
13
Chloroform
12.30
1.059
11.14
14
1,2-Dichloroethane
12.92
0.409
15
Methyl chloroform
13.12
0.325
3.258
16
Benzene
13.51
0.117
17
Carbon tetrachloride
13.64
1.451
1.077
18
1,2-Dichloropropane
14.26
0.214
19
Trichloroethylene
14.50
0.327
8.910
20
cis-1,3-Dichloropropene
15.31
21
trans-1,3-Dichloropropene
15.83
22
1,1,2-Trichloroethane
15.93
0.336
23
Toluene
16.17
0.092
24
1,2-Dibromoethane (EDB)
16.78
0.366
5.137
25
Tetrachloroethylene
17.31
0.324
1.449
26
Chlorobenzene
18.03
0.120
27
Ethylbenzene
18.51
0.092
28
m,p-Xylene
18.72
0.095
29
Styrene
19.12
0.143
30
1,1,2,2-Tetrachloroethane
19.20
9.856
31
o-Xylene
19.23
32
4-Ethyltoluene
20.82
0.100
33
1,3,5-Trimethylbenzene
20.94
0.109
34
1,2,4-Trimethylbenzene
21.46
0.111
35
m-Dichlorobenzene
21.50
36
Benzyl chloride
21.56
37
p-Dichlorobenzene
21.67
0.188
38
o-Dichlorobenzene
22.12
0.188
39
1,2,4-Trichlorobenzene
24.88
0.667
40
Hexachlorobutadiene
25.82
0.305
1.055
'Refer to Figures 15 and 16 for peak location.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-43
-------
Method TO-14A
VOCs
TABLE 8. TYPICAL RETENTION TIME (minutes) FOR SELECTED ORGANICS USING
GC/FID/ECD/PID ANALYTICAL SYSTEM FOR COMPENDIUM METHOD TO-14A1
( oni|"KHIIkl
Relenlion Time inunulesi
FID
ECD
I'll)
Acetylene
2.984
--
--
1,3-Butadiene
3.599
--
3.594
Vinyl chloride
3.790
--
3.781
Chloromethane
5.137
--
--
Chloroethane
5.738
--
~
Bromoethane
8.154
--
~
Methylene Chloride
9.232
--
9.218
trans-1,2-Dichloroethane
10.077
--
10.065
1,1 -Dichloroethane
11.190
--
--
Chloroprene
11.502
~
11.491
Perfluorobenzene
13.077
13.078
13.069
Bromochloromethane
13.397
13.396
13.403
Chloroform
13.768
13.767
13.771
1,1,1 -Trichloroethane
14.151
14.153
14.158
Carbon Tetrachloride
14.642
14.667
14.686
Benzene/1,2-Dichloroethane
15.128
--
15.114
Perfluorotoluene
15.420
15.425
15.412
Trichloroethylene
17.022
17.024
17.014
1,2-Dichloropropene
17.491
17.805
17.522
Bromodichloromethane
18.369
--
--
trans-1,3-Dichloropropylene
19.694
19.693
19.688
Toluene
20.658
~
20.653
cis- 1,3-Dichloropropylene
21.461
21.357
21.357
1,1,2-Trichloroethane
21.823
--
--
T etrachloroethy lene
22.340
22.346
22.335
Dibromochloromethane
22.955
22.959
22.952
Chlorobenzene
24.866
~
24.861
m/p-Xylene
25.763
~
25.757
Styrene/o-Xylene
27.036
--
27.030
Bromofluorobenzene
28.665
28.663
28.660
1,1,2,2-T etrachloroethane
29.225
29.227
29.228
m-Dichlorobenzene
32.347
32.345
32.342
p-Dichlorobenzene
32.671
32.669
32.666
o-Dichlorobenzene
33.885
33.883
33.880
Parian® 3700 GC equipped with J & W Megabore® DB 624 Capillary Column
(30 m x 0.53 I.D. mm) using helium carrier gas.
Page 14A-44
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
TABLE 9. GC/MS/SIM CALIBRATION TABLE FOR COMPENDIUM METHOD TO-14A
Last Update:
Reference Peak Window:
Non-Reference Peak Window:
Sample Amount:
18 Dec 96 7:54 am
5.00 Absolute Minutes
0.40 Absolute Minutes
0.000 Uncalibrated Peak RF: 0.000 Multiplier: 1.000
Ret lime
IV
Si»
nal Description
Ami pplv
I.vl
| A rca|
1 VTvpe
Partial Name
5.008
1
Mass
85.00 amu
13620
1
72974
1
FREON 12
5.690
2
Mass
50.00 amu
12720
1
36447
1
METHYLCHLORID
6.552
3
Mass
85.00 amu
8380
1
81251
1
FREON 114
6.709
4
Mass
62.00 amu
8050
1
20118
1
VINYLCHLORIDE
7.831
5
Mass
94.00 amu
12210
1
28265
1
METHYLBROMIDE
8.431
6
Mass
64.00 amu
12574
1
16149
1
ETHYLCHLORIDE
9.970
7
Mass
101.00 amu
12380
1
80088
1
FREON 11
10.927
8
Mass
61.00 amu
7890
1
38954
1
VINDENECHLORI
11.209
9
Mass
49.00 amu
12760
1
43507
1
DICHLOROMETHA
11.331
10
Mass
41.00 amu
12650
1
1945
1
ALLYLCHLORIDE
11.595
11
Mass
151.00 amu
7420
1
40530
1
3CHL3FLUETHAN
12.502
12
Mass
63.00 amu
12710
1
61595
1
UDICHLOETHA
13.403
13
Mass
61.00 amu
12630
1
50900
1
c-l,2DICHLETH
13.747
14
Mass
83.00 amu
7670
1
40585
1
CHLOROFORM
14.387
15
Mass
62.00 amu
9040
1
33356
1
1,2DICHLETHAN
14.623
16
Mass
97.00 amu
8100
1
38503
1
METHCHLOROFOR
15.038
17
Mass
78.00 amu
10760
1
69119
1
BENZENE
15.183
18
Mass
117.00 amu
8340
1
42737
1
CARBONTETRACH
15.829
19
Mass
63.00 amu
12780
1
38875
1
l,2DICHLPROPA
16.096
20
Mass
130.00 amu
8750
1
30331
1
TRICHLETHENE
16.956
21
Mass
75.00 amu
4540
1
17078
1
c-l,3DICHLPRO
17.492
22
Mass
75.00 amu
3380
1
13294
1
t-l,3DICHLPRO
17.610
23
Mass
97.00 amu
12690
1
32480
1
U-2CHLETHAN
17.862
24
Mass
91.00 amu
10010
1
88036
1
TOLUENE
18.485
25
Mass
107.00 amu
6710
1
33350
1
EDB
19.012
26
Mass
166.00 amu
7830
1
43454
1
TETRACHLETHEN
19.729
27
Mass
112.00 amu
7160
1
44224
1
CHLOROBENZENE
20.195
28
Mass
91.00 amu
12740
1
127767
1
ETHYLBENZENE
20.407
29
Mass
91.00 amu
25400
1
200973
1
m,p-XYLENE
20.806
30
Mass
104.00 amu
12390
1
38332
1
STYRENE
20.916
31
Mass
83.00 amu
11690
1
64162
1
TETRACHLETHAN
20.921
32
Mass
91.00 amu
11085
1
90096
1
o-XYLENE
22.528
33
Mass
105.00 amu
12560
1
108747
1
4-ETHYLTOLUEN
22.648
34
Mass
105.00 amu
12620
1
83666
1
1,3,5METHBENZ
23.179
35
Mass
105.00 amu
12710
1
79833
1
1,2,4METHBENZ
23.307
36
Mass
146.00 amu
12650
1
57409
1
m-DICHLBENZEN
23.317
37
Mass
91.00 amu
7900
1
50774
1
BENZYLCHLORID
23.413
38
Mass
146.00 amu
12390
1
58127
1
p-DICHLBENZEN
23.885
39
Mass
146.00 amu
13510
1
52233
1
o-DICHLBENZEN
26.714
40
Mass
180.00 amu
15520
1
18967
1
1,24CHLBENZE
27.680
41
Mass
225.00 amu
7470
1
43920
1
HEXACHLBUTADI
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-45
-------
Method TO-14A
VOCs
TABLE 10. EXAMPLE OF HARD-COPY OF GC/MS/SIM ANALYSIS BY
COMPENDIUM METHOD TO-14A
Quantitation Report
C:\HPCHEM\l\DATA\6D25M03.D
25 Apr 96 12:50 pm
AUDIT SAMPLE #239-54 250ML
Data File
Acq On
Sample
Misc :
Quant Time: Apr 25 IS;33 1996
Method
Title
Last Update
Response via
CCal File
C:\HPCHEM\1\M2TH0DS\AUDIT.M
Initial Calibration 4/8/96
Thu Apr 25 16.-36 ill 199S
Continuing Calibration
C:\HPCHEM\1\DATA\6D2 SMO1.D
Vial: 3
Operator: DANIELS
Inst : 5972 - In
Multiplr: 2.00
Std #4026-94
Abundance
i i
450000 J
400000 .
350000 .
300000 J
250000
200000 -
150000
100000 -
"TI'C: SD25K03 .13"
50000
—JJ
rime--> 5 . 00
iq
17
D
2
1$
14
i:
12
UJ
18
16
152!
liJ
39
38
3*0S
36 I
3*5
33
27
23
2
2
2!
(i°
23
24
u
32
,31
U
'b
41'
|#6
LJJ
ToToo
15.00
20:00
25100
48
47
-i 1 1 r-
30 . 00
Page 14A-46
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
TABLE 10. (continued)
Internal Standards
R.T. Qlon Response cone unics uevimaj
1) 3R0M0CHL0R0METHANE
17) 1,4-DIFLUOROBENZENE
27) CHL0R0BENZENE-D5
13.40 49
15,79 114
21.73 117
173440
383363
346909
System Monitoring Compounds
15) 1,2-DICHLOROETHANE-D4 14.39 65 177334
28) TOLUENE-D8 19.07 98 393347
40) BROMOFLUOROBENZENE 24.01 95 310217
4.8 0 PPBV
4.80 PPBV
4.80 PPBV
0. 00
0 .00
0.00
^Recovery
4.82 PPBV 100.33%
4.78 PPBV 99.61%
4.61 PPBV 95.94%
Target Compounds
Qvalue
2)
Freon 12
5.17
85
295965
7.67
PPBV
99
3)
Chloromethane
5.65
50
113926
7.96
PPBV
# 100
4)
Freon 114
5.94
85
376276
7.88
PPBV
97
5)
Chloroethene
6.25
62
113201
8.60
PPBV
100
6)
Broraomethane
7.26
94
106443
8.74
PPBV
96
7)
Chloroethane
7.64
64
57451
7.46
PPBV
99
3)
Freon 11
9.13
101
266209
7.77
PPBV
93
9)
1,1-Dichloroethene
10.21
61
186189
8.03
PPBV
99
10)
Methylene Chloride
10.35
49
153173
8.40
PPBV
99
11)
Freon 113
10.75
101
225115
7.85
PPBV
99
12)
1,1-Dichloroethane
12.05
63
211903
7. 80
PPBV
99
13)
cis-l,2-Dichloroethene
13 .16
61
170091
8.55
PPBV
99
14)
Chloroform
13.54
83
236380
8.15
PPBV
98
16)
l,2-Dichloroethane
14.53
62
144398
7.92
PPBV
100
18)
1,1,1-Trichloroethane
14.89
97
208233
7.72
PPBV
99
19)
Benzene
15.51
78
329475
8.45
PPBV
100
20)
Carbon Tetrachloride
15.70
117
215628
7.87
PPBV
99
21)
1,2-Dichloropropane
16.52
63
135206
7.80
PPBV
99
22)
Bromodiohloromethane
16.74
83
275403
8.98
PPBV
98
23)
Trichloroethene
16.80
95
139564
7.76
PPBV
100
24)
cis-l,3-Dichloropropene
17.84
75
97972
4.79
PPBV
98
25)
trans-1,3-Dichloropropene
18.49
75
27930
1.61
PPBV
100
26)
1,1,2-Trichloroethane
18.01
97
120253
7.66
PPBV
98
29)
Toluene
19.22
91
334990
7.69
PPBV
97
30)
Dibromochloromethane
19.85
129
243321
8.35
PPBV
99
31)
1,2-Dibromoethane
20.23
107
173047
7.17
PPBV
100
32)
Tetrachloroethene
20.81
166
145120
7.91
PPBV
99
33)
Chlorobenzene
21.80
112
253495
7.80
PPBV
97
34)
Ethylbenzene
22.28
91
454612
8.32
PPBV
99
35)
m,p-Xylene
22.53
91
561168
12. 91
PPBV
99
36)
Bromoform
22.80
173
210707
8.71
PPBV
100
37)
Styrene
23.09
104
133812
5. 06
PPBV
99
38)
1,1,2,2-Tetrachloroethane
23.24
83
268481
6 .70
PPBV
99
39)
o-Xylene
23.28
91
257133
5.29
PPBV
100
41)
1,3,5-Trimethylbenzene
25.37
105
198466
4 .39
PPBV
99
42)
1,2,4-Trimethylbenzene
26.15
105
160459
3.49
PPBV
99
43)
Benzyl chloride
26.47
91
107354
6.40
PPBV
99
44)
1,3-Dichlorobenzene
26.55
146
106397
6.44
PP3V
99
45)
1,4-Dichlorobenzene
26.66
146
180374
6.04
PPBV
99
46)
1,2-Dichlorobenzene
27.36
146
164427
6.03
PPBV
99
47)
1,2,4-Trichlorobenzene
Hexachlorobutadiene
31.19
180
42255
2.96
PPBV
99
48)
32.45
225
56763
3 .47
PPBV
99
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-47
-------
Method TO-14A
VOCs
Receive Sample
Canister (Section
9.2.2)
<83 kPa
(Optional)
Analyze
Log Sample in Analytical
Logbook (Section 10.4.1.2)
Calculate Dilution Factor
(Section 10.4.1.4)
Pressurize with N2
to 1.38 kPa (20 psig)
Record Final Pressure
(Section 10.4.1.3)
Check and Record Initial
Pressure (Section 10.4.1.3)
GC/MS/SIM
(Section 10.4.3)
GC/MS/SCAN
(Section 10.4.2)
GC-Multidetector
(GC/FID/ECD/PID)
(Section 10.4.4)
1
Non-Specific Detector (FID)
(Optional)
Figure 1. Analytical systems available for canister VOC identification and quantitation
as part of Compendium Method TO-14 A.
Page 14A-48
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
To AC
Insulated Enclosure
_ Inlet
Manifold
" 1.6 Meters
Metal Bettowj ;
Type Pump *]**
for Pressurized I I
Sampling | | f
' LH
Mas# Flow Meter
Auxillioiy
Vacuum
Rump
Moss Flow
Control Unit
O Q
QOQQQQ
Heater
Fan
Figure 2. Example of sampler configuration for subatmospheric pressure or
pressurized canister sampling used in Compendium Method TO-14A.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-49
-------
Method TO-14A
VOCs
Heated Enclosure
J Vent
Inlet
*"• 1.6
Meters
(~S Ft)
Ground
Level
LI U
flJL
rtfi
Pump
Inlet Manifold
T
Auxilliary
Vacuum
Pump
Thermostat
7T
AI
Fan
Pressure
Gauge
Mechanical
Flow
Regulator
Water
Trap
T
Vent
Electronic
Timer
o
Heater
Vacuum/Pressure
Gauge
s
\
Vent
Magnelatch
Valve
Valvej
Canister
To AC
Figure 3. Example of alternative sampler configuration for pressurized canister sampling
used in Compendium Method TO-14A.
Page 14A-50
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
Pressure
Regulator
Moss Row
Controller
Mass Row
Controller
Gas
Purifier
Pump
6-Port
Chromatographic
Valve
Nofiori
Dryer
Dry
Forced
Air in
Exhaust
Optional
Pressure
Cryogenic
Trapping
Unit
I Mass Row
I Controller
Pressure
Regulators
Purifiers
Carrier
Gas
OV-1
Capillary
Column
(0.32-mm x 50-m)
Low Dead—Volume
Tee (Optional)
—c::>~
ri_
Flame Ionization
Detector (FID)
I I
I I
I I
Flow
Rest ric tor
(Optional)
Mass Spectrometer In
SCAN/SIM Mode
Figure 4. Compendium Method T0-14A canister analysis utilizing GC/MS/SCAN/SIM
analytical system with optional FID with 6-port valve.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-51
-------
Method TO-14A
VOCs
Page 14A-52
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
H Ipf
a m
c3
O
c3
§
Q
O dj
W -T3
Q I
^ s
O .2
O a,
o o
g
•s ja
£ a
T3 fl
« B
es M
'3 _g
o £
m tl
Cfl
c3 •==
s g
o ji;
C3
c3 >
O
a-
-A
® a
fl c?
8 &
a %
& a
£ §
frJ3
<3 °
^ ti
-H O
o *
H
^ -a
£ £
.ti
S *
a a
g
&
a
o
O
vd
a
11 f-r
5£«1
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-53
-------
Method TO-14A
VOCs
Pressure
Regulator
3-Port
Gas
Valve
Exhaust ^
Zero
Air
Supply
Vacuum Pump
Shut Off Valve
Vent
Valve
Check Valve
Vacuum
Pump
Exhaust
Dewor
Flask
Vent Shut
Off Valve
Trap
Vent Shut
Off Valve
Cryogenic
Trap Cooler
(Liquid Argon)
Zero
Air
Supply
Dewar
Flask
Pressure
Regulator
Humidifier
Trap
Cryogenic
Trap Cooler
(Liquid Argon)
Vacuum
Shut Off
Valve
Pressure
Gauge
Vacuum
Gauge '
Zero
Shut Off
Valve
Row
Control
Valve
Vacuum
Gauge
Shut Off
Valve
Exhaust ^
Manifold
Vent
Shut Off
Valve
. Optional
Isothermal
Oven
Sample \ ( Sample \ / Sample
Canister ) I Canister I \ Canister
Figure 7. Compendium Method TO-14A canister cleaning system.
Page 14A-54
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
lenoqiq
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
Method TO-14A
VOCs
TIMER
SWITCH
115 V AC
100K
j2n
RED
-N—
AOnta. 450 V DC
R» 100K 01
BLACK
-rt—
*2 100K
?
40/tfd. 450 V DC
CopociUk Ci ond Cz - 40 uf. 490 vDC (Sprogue Atom TV* 1712 or equwonent)
Mr Ri ond Rj - OA aoU, 5* tolerance
i Di ond D* - 1000 PW. 2.5 A (RCA, SK 30B1 or iqunM)
(a). Simple Circuit for Operating Magnelatch Valve
RED
TIMER
SWITCH
BLACK
115 V AC
AC
12.7K
2.7K
BRIDCE
RECTIFIER
200 u f
PUUP
10K
COIL
AC
WHITE
20 uf
400 Volt
mU=fiQLABZED
Bridge Rectifier - 200 PRv. 1.5 A (RCA SK 310ft or equivalent)
IV. rf. |\. Mi It. _ 1MM aau 41 A fOfA Clt IM1 « -¦
SK
or
02 - 1000 PRV. 2.5 A (RCA. SK 3081 or e**tfent)
COporitor Ci - 200 uf. 250 VDC (Sprogue Atom IV* 1528 or equivalent)
Coporitor Ci - 20 uf. 400 VOC Non-Polorfeed (Sprogue Atom IVAN 1652 or eqvvolertl)
Rtfojr - 10.000 ohm a£. 3.5 mo (ahF Potter ond Brumfieid. KCP 5. or equivalent)
ResMer Ri ond R* - OA "OU, 5JK tolerance
(b). Improved Circuit Designed to Handle Power Interruptions
Figure 9. Compendium Method TO-14A electrical pulse circuits for driving skinner
magnelatch solenoid valve with a mechanical timer.
Page 14A-56 Compendium of Methods for Toxic Organic Air Pollutants January 1999
-------
VOCs
Method TO-14A
COMPENDIUM METHOD TO-14A
CANISTER FIELD TEST DATA SHEET
GENERAL INFORMATION
SITE LOCATION:
SITE ADDRESS:
SHIPPING DATE:
CANISTER SERIAL NO.:
SAMPLER ID:
OPERATOR:
SAMPLING DATE:
CANISTER LEAK
CHECK DATE:
B. SAMPLING INFORMATION
TEMPERATURE
PRESSURE
INTERIOR
AMBIENT
MAXIMUM
MINIMUM
START
STOP
CANISTER PRESSURE
SAMPLING TIMES
FLOW RATES
LOCAL
TIME
ELAPSED TIME
METER READING
START
STOP
MANIFOLD
n.ow rail;
CANISTER
flow rait;
l-LOW CONTROLLER
READOUT
SAMPLING SYSTEM CERTIFICATION DATE:
QUARTERLY RECERTIFICATION DATE:
C. LABORATORY INFORMATION
DATA RECEIVED:
INITIAL PRESSURE:
FINAL PRESSURE:
ANALYSIS
GC/FID/ECD DATE:
DILUTION FACTOR:
RESULTS*:
GC/MSD/SCAN DATE:
GC/MSD/SIM DATE:
GC/FID/ECD: _
GC/MSD/SCAN:
GC/MSD/SIM:
SIGNATURE/TITLE
*ATTACH DATA SHEETS
Figure 10. Compendium Method TO-14A field test data sheet (FTDS).
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-57
-------
Method TO-14A
VOCs
TIME
hujli,
(a) SCAN analysis
^ JA l\kLuu*»vL_
£
t/>
jU J ft 1^,
TIME
(b) SIM analysis
(/>
¦ Tiur _
VL-J
JJA
y
lid
TIME
(c) FID analysis
£
in
I TIME
J L
(d) ECD analysis
Figure 11. Compendium Method TO-14A typical chromatograms of a VOC sample
analyzed by GC/MS/SCAN/SIM mode and GC-multidetector mode.
Page 14A-58
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
Cryogen
Exhaust
Insulated Shell
Cylindricolly Wound
Tube Heater (250 watt)
Trap
Sample
Bracket and
Cartridge
Heaters (25 watt)
t
Cryogen in
(Liquid Nitrogen)
Figure 12. Example of Compendium Method TO-14A cryogenic trapping unit.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-59
-------
Method TO-14A
VOCs
Receive Sample
Canister (Section
9.2.2}
<83 kPa
(12 psig)
(Optional)
External
Standard
Calibration
Record Final Pressure
(Section 10.4.1.5)
Calculate Dilution Factor
(Section 10.4.1.4)
Log Sample in Laboratory
Logbook (Section 10.4.1.2)
Pressurize with N
to 1.38 kPa (20 psit
Daily One (1) Point Static Calibration
Initial Three (3) Point Static Calibration
Additional Five (5) Point Static
Calibration for Nonlinear Compounds
Initial Preparation and Tuning
Additional Three (3) Point Static
Calibration for Nonlinear Compounds
Humid Zero Air Test
Routine Preparation and Tuning
Humid Zero Air Test
GC/MS/SCAN/SIM
(with Optional FID)
Analytical System
Check and Record
Initial Pressure
(Section 10.4.1.3)
Preparation of
GC/MS/SCAN/SIM (with
Optional FID) Analytical
System or GC/lon Trap
Figure 13. Compendium Method TO-14A flowchart of GC/MS/SCAN/SIM analytical
system preparation (with optional FID system).
Page 14A-60
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
Receive Sample
Canister (Section
9.2.2)
<83 kPa
(12 psig)
(Optional)
External
Standard
Calibration
Analyze
Record Final Pressure
{Section 10.4.1.3)
Calculate Dilution Factor
(Section 10.4.1.4)
Routine Preparation
Preparation of GC/FID/ECD/PID
Analytical System
Log Sample in
(Section 10.4.1.2)
GC/FID/ECD/PID
Analysis for Primary Quantitation
Pressurize with N2
to 1.38 kPa (20 psig)
Initial Preparation
Daily One (1) Point Static Calibration
Humid Zero Air Test and
Retention Time Window Test
Additional Three (3) Point Static
Calibration for Nonlinear Compounds
Humid Zero Air Test and
Retention Time Window Test
Initial Three (3) Point Static Calibration
Additional Five (5) Point Static
Calibration for Nonlinear Compounds
Check and Record
Initial Pressure
(Section 10.4.1.3)
Figure 14. Compendium Method TO-14A flowchart of GC/FID/ECD/PID analytical
system preparation.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-61
-------
Method TO-14A
VOCs
C
TJ
S
a.
o
k
to
A
O
Q)
t/i
Xjifiuaiui
Page 14A-62
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
X]ISU3)U|
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-63
-------
Method TO-14A
VOCs
TIME
(o). Certified Sompler
J iaI
TIME
(b). Contaminated Sompler
Figure 17. Example of humid zero air test results for a clean sampler (a)
and a contaminated sampler (b) used in Compendium Method TO-14A.
Page 14A-64
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
1000 —
900 —
~00 —
g 700 -
X 600 —
w
.2 500 —
c
3
g 400-
8 300 —
200 —
100 —
0
23456709 10
1
Concentration (ppbv)
FIGURE 18(a). NONLINEAR RESPONSE OF
TETRACHLOETHYLENE ON THE ECD
1000 —
900 —
800 —
g 700 -
X BOO —
500 —
400 —
U 300 —
200 —
100 —
0
234S67S9 10
1
Concentration (ppbv)
FIGURE 18(c). NONLINEAR RESPONSE OF
HEXACHLOROBUTADIENE ON THE ECD
1100
—
1000
-
900
—
BOO
—
o
o
700
—
><
600
-
c
3
8
500
400
S
k
300
200
100
—
0 / I I I I I I I I I I
0 1 23455789 10
Concentration (ppbv)
FIGURE 18(b). NONLINEAR RESPONSE OF
CARBON TETRACHLORIDE ON THE ECD
ISO —
140 —
120 —
X 100 —
80 —
SO —
40 —
20 —
0123456789 10
Concentration (ppbv)
FIGURE 18(d). LINEAR RESPONSE OF
CHLOROFORM ON THE ECD
Figure 18. Response of ECD to various VOCs as part of Compendium Method T0-14A.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-65
-------
Method TO-14A
VOCs
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
SCAN Mode
SIM Mode
Canister Receipt
Check Canister Pressure
Record Initial/Final Pressure
Calculate Dilution Factor
External
Standard
Calibration
External
Standard
Calibration
Pressure with N2
to 15-20psig
Daily One (1) Point
Dynamic Calibration
Daily One (1) Point
Dynamic Calibration
GC/FID/ECD/PID
Analytical Preparation
Humid Zero Air Test
Daily One (1) Point
Dynamic Calibration
Daily One (1) Point
Dynamic Calibration
Humid Zero Air Test
Humid Zero Air Test
Humid Zero Air Test
Routine Preparation
Routine Preparation
GC/MS Analytical
Preparation
Routine Preparation
Routine Preparation
GC/FID/ECD and GC/MS
Sample Analysis
GC/MS/SIM Selected VOCs for
Identification and Quantitation
GC/MS/SCAN Identification and
Semi-quantitation of VOCs
GC/FID/ECD/PID
Screening Analysis
Record Sample Canister in Dedicated Logbook
Additional Three (3) Point Dynamic Calibration
for Nonlinear Compounds
Additional Three (3) Point Dynamic Calibration
for Nonlinear Compounds
Additional Five (5) Point Static Dynamic
Calibration for Nonlinear Compounds
Additional Three (3) Point Static Dynamic
Calibration for Nonlinear Compounds
Figure 20. Flowchart of analytical systems preparation used in Compendium Method TO-14A.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-67
-------
Method TO-14A
VOCs
C CM
-Q CO
o
c
D.
b
E
W
S.
<0
ro
O
N O
CO
o "5
I o
? ©
£ §
_ c c jQ :
o O c £ Q ® c
^E°c{3fv+-
+3 (TJ "R +3 _ P
O O
5. i tit,
g <£.55 to Q <
I
c | .12
-¦§! i g
Sg-S'-g
¦® n S
£C Q CO
el 2
0) (0 T-
T) += O
£ i '¦§
3 O ®
x <0
CO
c g
C£'E
® S A c <=>
¦£ E S >> 8 7
?£°§o|
*3 ff 1
o '5 o
if i
— raj $
,
Page 14A-68
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
Appendix A
Availability Of VOC Standards From United States Environmental Protection Agency
1. Availability of Audit Cylinders
1.1 At the time of the publication of the original Compendium Method TO-14, the USEPA provided cylinder
gas standards of hazardous organic compounds at the ppb level. These standards were used to audit the
performance of monitoring systems such as those described in the original Compendium Method TO-14.
However, this service is no longer provided.
1.2 To obtain information about the availability of different audit gases, interested parties are encouraged to call
commercial gas suppliers.
2. Audit Cylinder Certification
2.1 All audit cylinders should be periodically analyzed to assure that cylinder concentrations have remained
stable.
2.2 All audit gases, including quality control analyses, of ppbv hazardous VOC standards should be traceable
to NIST.
3. Information on EPA's VOC Standards
3.1 USEPA program/regional offices, state/local agencies, and others may obtain advice and information on
VOC standards by calling:
Mr. Howard Christ
U.S. Environmental Protection Agency
National Exposure Research Laboratory (NERL)
Research Triangle Park, NC 27711
919-541-4531
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-69
-------
Method TO-14A
VOCs
[This page intentionally left blank]
Page 14A-70 Compendium of Methods for Toxic Organic Air Pollutants January 1999
-------
VOCs
Method TO-14A
Appendix B
Operating Procedures For A Portable Gas Chromatograph Equipped
With A Photoionization Detector
1. Scope
This procedure is intended to screen ambient air environments for volatile organic compounds. Screening is
accomplished by collection of VOC samples within an area and analysis on site using a portable gas
chromatograph/integrator. This procedure is not intended to yield quantitative or definite qualitative information
regarding the substances detected. Rather, it provides a chromatographic "profile" of the occurrence and intensity
of unknown volatile compounds which assists in placement of fixed-site samplers.
2. Applicable Documents
2.1 ASTM Standards
• E260 Recommended Practice for General Gas Chromatography Procedures
• E355 Practice for Gas Chromatography Terms and Relationships
2.2 Other Documents
Portable Instruments User's Manual for Monitoring VOC Sources. EPA-34011-86-015. IJ. S. Environmental
Protection Agency, Washington, DC, June, 1986.
3. Summary of Method
3.1 An air sample is extracted directly from ambient air and analyzed on site by a portable GC.
3.2 Analysis is accomplished by drawing an accurate volume of ambient air through a sampling port and into
a concentrator, then the sample air is transported by carrier gas onto a packed column and into a PID, resulting
in response peak(s). Retention times are compared with those in a standard chromatogram to predict the probable
identity of the sample components.
4. Significance
4.1 VOCs are emitted into the atmosphere from a variety of sources including petroleum refineries, synthetic
organic chemical plants, natural gas processing plants, and automobile exhaust. Many of these VOC emissions
are acutely toxic; therefore, their determination in ambient air is necessary to assess human health impacts.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-71
-------
Method TO-14A
VOCs
4.2 Conventional methods for VOC determination use solid sorbent and canister sampling techniques.
4.3 Collection of ambient air samples in canisters provides (1) convenient integration of ambient samples over
a specific time period, (e.g., 24 hours); (2) remote sampling and central analysis; (3) ease of storing and shipping
samples, if necessary; (4) unattended sample collection; (5) analysis of samples from multiple sites with one
analytical system; and (6) collection of sufficient sample volume to allow assessment of measurement precision
and/or analysis of samples by several analytical systems.
4.4 The use of portable GC equipped with multidetectors has assisted air toxics programs by using the portable
GC as a "screening tool" to determine "hot spots," potential interferences, and semi-quantitation of VOCs, prior
to locating more traditional fixed-site samplers.
5. Definitions
Definitions used in this document and in any user-prepared Standard Operating Procedures (SOPs) should be
consistent with ASTM Methods D1356 and E355. Abbreviations and symbols pertinent to this method are
defined at point of use.
6. Interferences
6.1 The most significant interferences result from extreme differences in limits of detection (LOD) among the
target VOCs (see Table B-1). Limitations in resolution associated with ambient temperature, chromatography
and the relatively large number of chemicals result in coelution of many of the target components. Coelution of
compounds with significantly different PID sensitivities will mask compounds with more modest sensitivities.
This will be most dramatic in interferences from benzene and toluene.
6.2 A typical chromatogram and peak assignments of a standard mixture of target VOCs (under the prescribed
analytical conditions of this method) are illustrated in Figure B-l. Samples which contain a highly complex
mixture of components and/or interfering levels of benzene and toluene are analyzed on a second, longer
chromatographic column. The same liquid phase in the primary column is contained in the alternate column but
at a higher percent loading.
6.3 Recent designs in commercially available GCs have preconcentrator capabilities for sampling lower
concentrations of VOCs, pre-column detection with back-flush capability for shorter analytical time, constant
column temperature for method precision and accuracy and multidetector (PID, ECD, and FID) capability for
versatility. Many of these newer features address the weaknesses and interferences mentioned above. A list of
major manufacturers of portable GC systems is provided in Table B-2.
7. Apparatus
7.1 Gas Chromatogram
A GC, Photovac Inc., 739 B Parks Ave, Huntington, NY 11743, Model 10S10 or 10S50, or equivalent used for
surveying ambient air environments (which could employ a multidetector) for sensing numerous VOCs
compounds eluting from a packed column at ambient temperatures. This particular portable GC procedure is
Page 14A-72
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
written employing the photoionization detector as its major sensing device, as part of the portable GC survey tool.
Chromatograms are developed on a column of 3% SP-2100 on 100/120 supelcoport (0.66-m x 3.2-mm I.D.) with
a flow of 30 mL/min air.
7.2 GC Accessories
In addition to the basic gas chromatograph, several other pieces of equipment are required to execute the survey
sampling. Those include gas-tight syringes for standard injection, alternate carrier gas supplies, high pressure
connections for filling the internal carrier gas reservoir, and if the Model 1 OS 10 is used, a recording integrator.
8. Reagents and Materials
8.1 Carrier Gas
"Zero" air [<0.1 ppm total hydrocarbon(THC)] is used as the carrier gas. This gas is conveniently contained in
0.84 m3 (30 If ) aluminum cylinders. Carrier gas of poorer quality may result in spurious peaks in sample
chromatograms. A Brooks, Type 1355-00F1AAA rotameter (or equivalent) with an R-215-AAA tube and glass
float is used to set column flow.
8.2 System Performance Mixture
A mixture of three target compounds (e.g., benzene, trichloroethylene, and styrene) in nitrogen is used for
monitoring instrument performance. The approximate concentration for each of the compounds in this mixture
is 10 parts per billion (ppb). This mixture is manufactured in small, disposable gas cylinders [at 275 kPa (40
psi)] various commercial vendors.
8.3 Reagent Grade Nitrogen Gas
A small disposable cylinder of high purity nitrogen gas is used for blank injections.
8.4 Sampling Syringes
Gas-tight syringes, without attached shut-off valves (Hamilton Model 1002LT, or equivalent) are used to
introduce accurate sample volumes into the high pressure injectors on the portable gas chromatograph. Gas
syringes with shut-off valves are not recommended because of memory problems associated with the valves. For
samples suspected of containing high concentrations of volatile compounds, disposable glass syringes (e.g.,
Glaspak, or equivalent) with stainless steel/Teflon® hub needles are used.
8.5 High Pressure Filter
An adapter (Photovac SA101, or equivalent) for filling the internal carrier gas reservoir on the portable GC is
used to deliver "zero" air.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-73
-------
Method TO-14A
VOCs
9. Procedure
9.1 Instrument Setup
9.1.1 The portable gas chromatograph must be prepared prior to use in the ambient survey sampling. The
pre-sampling activities consist of filling the internal carrier gas cylinder, charging the internal power supply,
adjusting individual column carrier gas flows, and stabilizing the photoionization detector.
9.1.2 The internal reservoir is filled with "zero" air. The internal 12V battery can be recharged to provide
up to eight hour of operation. A battery which is discharged will automatically cause the power to the instrument
to be shut down and will require an overnight charge. During AC operation, the batteries will automatically be
trickle-charged or in a standby mode.
9.1.3 The portable GC should be operated (using the internal battery power supply) at least forty minutes
prior to collection of the first sample to insure that the photoionization detector has stabilized. Upon arriving at
the area to be sampled, the unit should be connected to AC power, if available.
9.2 Sample Collection
9.2.1 After the portable gas chromatograph is located and connected to 110V AC, the carrier gas glows must
be adjusted. Flows to the 1.22 meter, 5% SE-30 and 0.66 meter, 3% SP2100 columns are adjusted with needle
valves. Flows of 60 mL/min (5% SE-30) and 30 mL/min (3% SP2100) are adjusted by means of a calibrated
rotameter. Switching between the two columns is accomplished by turning the valve located beneath the
electronic module. During long periods of inactivity, the flows to both columns should be reduced to conserve
pressure in the internal carrier gas supply. The baseline on the recorder/integrator is set to 20% full scale.
9.2.2 Prior to analysis of actual samples, an injection of the performance evaluation mixture must be made
to verity chromatographic and detector performance. This is accomplished by withdrawing 1.0 mL samples of
this mixture from the calibration cylinder and injecting it onto the 3% SP2100 column. The next sample
analyzed should be a blank, consisting of reagent grade nitrogen.
9.2.3 Ambient air samples are injected onto the 3% SP2100 column. The chromatogram is developed for
15 minutes. Samples which produce particularly complex chromatograms, especially for early eluting
components, are reinjected on the 5% SE-30 column.
[Note: In no instance should a syringe which has been used for the injection of the calibrant/system
performance mixture be use for the acquisition and collection of samples, or vice versa.]
9.2.4 Samples have generally been collected from the ambient air at sites which are near suspected sources
of VOCs and compared with those which are not. Typically, selection of sample locations is based on the
presence of chemical odors. Samples collected in areas without detectable odors have not shown significant PID
responses. Therefore, sampling efforts should be initially concentrated on "suspect" environments (i.e., those
which have appreciable odors). The objective of the sampling is to locate sources of the target compounds.
Ultimately, samples should be collected throughout the entire location, but with particular attention given to areas
of high or frequent occupation.
Page 14A-74
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
9.3 Sample Analysis
9.3.1 Quantitative Analysis. Positive identification of sample components is not the objective of this
"screening" procedure. Visual comparison of retention times to those in a standard chromatogram (Figure B-l)
are used only to predict the probable sample component types.
9.3.2 Estimation of Levels. As with qualitative analysis, estimates of component concentrations are
extremely tentative and are based on instrument responses to the calibrant species (e.g., benzene,
trichloroethylene, styrene), the proposed component identification, and the difference in response between sample
component and calibrant. For purposes of locating pollutant emission sources, roughly estimated concentrations
and suspected compound types are considered sufficient.
10. Performance Criteria and Quality Assurance
Required quality assurance measures and guidance concerning performance criteria that should be achieved within
each laboratory are summarized and provided in the following section.
10.1 Standard Operating Procedures
10.1.1 SOPs should be generated by the users to describe and document the following activities in their
laboratory: (1) assembly, calibration, leak check, and operation of the specific portable GC sampling system and
equipment used; (2) preparation, storage, shipment,and handling of the portable GC sampler; (3) purchase,
certification, and transport of standard reference materials; and (4) all aspects of data recording and processing,
including lists of computer hardware and software used.
10.1.2 Specific stepwise instructions should be provided in the SOPs and should be readily available to and
understood by the personnel conducting the survey work.
10.2 Quality Assurance Program
10.2.1 Reagent and Materials Control. The carrier gas employed with the portable GC is "zero air"
containing less than 0.1 ppm VOCs. System performance mixtures are certified standard mixtures purchased
form Scott Specialty Gases, or equivalent.
10.2.2 Sampling Protocol and Chain of Custody. Sampling protocol sheets must be completed for each
sample. Specifics of the sample with regard to sampling location, sample volume, analysis conditions, and
supporting calibration and visual inspection information are detailed by these documents. An example form is
exhibited in Table B-3.
10.2.3 Blanks, Duplicates, and System Performance Samples.
10.2.3.1 Blanks and Duplicates. Ten percent of all injections made to the portable GC are blanks, where
the blank is reagent grade nitrogen gas. This is the second injection in each sampling location. An additional
10% of all injections made are duplicate injections. This will enhance the probability that the chromatograph of
a sample reflects only the composition of that sample and not any previous injection. Blank injections showing
a significant amount of contaminants will be cause for remedial action.
10.2.3.2 System Performance Mixture. An injection of the system performance mixture will be made
at the beginning of a visit to a particular sampling location (i.e., the first injection). The range of acceptable
chromatographic system performance criteria and detector response is shown in Table B-4. These criteria are
selected with regard to the intended application of this protocol and the limited availability of standard mixtures
in this area. Corrective action should be taken with the column or PID before sample injections are made if the
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-75
-------
Method TO-14A
VOCs
performance is deemed out-of-range. Under this regimen of blanks and system performance samples,
approximately eight samples can be collected and analyzed in a three hour visit to each sampling location.
10.3 Method Precision and Accuracy
The purpose of the analytical approach outlined in this method is to provide presumptive information regarding
the presence of selected VOCs emissions. In this context, precision and accuracy are to be determined. However,
quality assurance criteria are described in Section 10.2 which insure the samples collected represent the ambient
environment.
10.4 Range and Limits of Detection
The range and limits of detection of this method are highly compound dependent due to large differences in
response of the portable GCs photoionization detector to the various target compounds. Aromatic compounds
and olefinic halogenated compounds will be detected at lower levels than the halomethanes or aliphatic
hydrocarbons. The concentration range of application of this method is approximately two orders of magnitude.
TABLE B-l. ESTIMATED LIMITS OF DETECTION (LOD) FOR
SELECTED VOCs BASED ON 1 yL SA1V
1PLE VOLUME
( i)ni|HHIIkl
I.OI) (ii'ji
I.OI) (pphi
Chloroform1
2
450
1,1,1-Trichloroethane1
2
450
Carbon tetrachloride1
2
450
Benzene
.006
2
1,2-Dichloroethane2
.05
14
Trichloroethylene2
.05
14
T etrachloroethylene2
.05
14
1,2-Dibromoethane
.02
2
p-Xylene3
.02
4
m-Xylene3
.02
4
o-Xylene4
.01
3
Styrene4
.01
3
Chloroform, 1,1,1-trichloroethane, and carbon tetrachloride
coelute on 0.66-m 3% SP2100.
2l,2-Dichloroethane, tricholroethylene, and tetrachloroethylene
coelute on 0.66-m 3% SP2100.
3p-Xylene and m-xylene coelute on 0.66-m 3% SP2100.
4Styrene and o-xylene coelute on 0.66-m 3% SP2100.
Page 14A-76
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
TABLE B-2. LIST OF COMMERCIALLY AVAILABLE PORTABLE
VOC INSTRUMENT MANUFACTURERS
Viking Instruments Corporation
3800 Concorde Parkway
Chantilly, VA 22021
Phone(703)968-0101
FAX (703) 968-0166
Photovac International Inc.
25-B Jefryn Boulevard
Deer Park, NY 11729
Phone (516)254-4199
FAX (516)254-4284
MSA Baseline
North Star Route PO Box 649
Lyons, CO 80540
Phone (303) 823-6661
FAX (303) 823-5151
SRI Instruments Inc.
3882 Del Amo Boulevard
Suite 601
Torrance, CA 90503
Phone (310)214-5092
FAX (310)214-5097
MTI Analytical Instruments
41762 Christy Street
Fremont, CA 94538
Phone (510)490-0900
FAX (510)651-2498
Sentex Sensing Technology
552 Broad Avenue
Ridgefield, NJ 07657
Phone (201)945-3694
FAX (201)941-6064
CMS Research Corporation
200 Chase Park South, Suite 100
Birmingham, AL 35244
Phone (205) 733-6910
FAX (205) 733-6919
HNU Systems Inc.
160 Charlemont Street
Newton Highlands, MA 021161-9987
Phone (617)964-6690
FAX (617) 965-5812
Microsensor Systems Inc.
62 Corporate Court
Bowling Green, KY 42104
Phone (502)745-0099
FAX (502) -
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-77
-------
Method TO-14A
VOCs
TABLE B-3. PORTABLE GAS CHROMATOGRAPH SAMPLING DATA SHEET
DATE: LOCATION: TIME:
CHROMATOGRAPHIC CONDITIONS:
COLUMN 1: COLUMN TYPE:
I.D. (mm): LENGTH (mm): FLOW (mL/min):
( Oi l \l\ 2: COLUMN TYPE:
I.D. (mm): LENGTH (mm): FLOW (mL/min):
l\ l \() TNJ VOL COLUMN NO SETTING LOCATION
SITE PLAN (indicate sampling locations):
DATE SIGNATURE
Page 14A-78
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
TABLE B-4. SYSTEM PERFORMANCE CRITER]
A FOR PORTABLE GC1
( rilei ia
Tesl ( oni|HHind
AcccpUihlc Ran.LV
Sii'j'jesled ( i)iivcli\c Aclion
PID Response
Elution Time
Resolution2
Trichloroethylene
Styrene
Benzene/Trichloro-ethylene
> 108uV-sec/ng
2.65 ± 0.15 min
> 1.4
Re-tune or replace lamp
Inspect for leaks, adjust carrier flow
Replace column
1 Based on analysis of a vapor mixture of benzene, styrene, and trichloroethylene.
2Define by: R + = 2d/(W|+W;): where d = distance between the peaks and W = peak width at
base.
TABLE B-5. ESTIMATED LIMITS OF
DETECTION (LOP) FOR SELECTED VOCs
( oniinHind
I.OI) (ii'ji
I.OI) (pphi
Chloroform1
2
450
1,1,1 -Trichloroethane1
2
450
Carbon tetrachloride1
2
450
Benzene
.006
2
1,2-Dichloroethane2
.05
14
Trichloroethylene2
.05
14
T etrachloroethylene2
.05
14
1,2-Dibromoethane
.02
2
p-Xylene3
.02
4
m-Xylene3
.02
4
o-Xylene4
.01
3
Styrene4
.01
3
Chloroform, 1,1,1-trichloroethane, and carbon tetrachloride
coelute on 0.66-m 3% SP2100.
2l,2-Dichloroethane, tricholroethylene, and
tetrachloroethylene coelute on 0.66-m 3% SP2100.
3p-Xylene and m-xylene coelute on 0.66-m 3% SP2100.
4Styrene and o-xylene coelute on 0.66-m 3% SP2100.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-79
-------
Method TO-14A
VOCs
Peok Assignments for Stondord Mixtures
Peak No.
Compound(s) 0
1
Benzene; Chloroform;
1,1,1 —Trichloroethone;
Corbon Tetrachloride
2
1,2-Dichioroethone;
Trichloroethylene
3
Tetrochloroethylene;
1,2-Dibromoethone
4
Ethyl benzene
5
m.n—Xylene
6
A-Xylene; Styrene
Toluene (not listed) elutes between
peoks 1 ond 2.
Time
Figure B-l. Typical chromatogram of VOCs determined by a portable GC.
Page 14A-80
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
Appendix C
Installation And Operation Procedures For U.S. Environmental
Protection Agency's Urban Air Toxic Monitoring Program Sampler
1. Scope
1.1 The subatmospheric sampling system described in this method was designed specifically for use in USEPA's
Urban Air Toxic Monitoring Program (UATMP) to provide analytical support to the states in their assessment
of potential health risks from certain toxic organic compounds that may be present in urban atmospheres.
1.2 The sampler is based on the collection of whole air samples in 6-liter, specially prepared passivated stainless
steel canisters. The sampler features electronic timer for ease, accuracy and flexibility of sample period
programming, an independently setable presample warm-up and ambient air purge period, protection from loss
of sample due to power interruptions, and a self-contained configuration housed in an all-metal portable case, as
illustrated in Figure C-l.
1.3 The design of the sampler is pumpless, using an evacuated canister to draw the ambient sample air into itself
at a fixed flow rate (3-5 mL/min) controlled by an electronic mass flow controller. Because of the relatively low
sample flow rates necessary for the integration periods, auxiliary flushing of the sample inlet line is provided by
a small, general-purpose vacuum pump (not in contact with the sample air stream). Further, experience has
shown that inlet lines and surfaces sometimes build up or accumulate substantial concentrations of organic
materials under stagnant (zero flow rate) conditions. Therefore such lines and surfaces need to be purged and
equilibrated to the sample air for some time prior to the beginning of the actual sample collection period. For this
reason, the sampler includes dual timers, one of which is set to start the pump several hours prior to the specified
start of the sample period to purge the inlet lines and surfaces. As illustrated in Figure C-l, sample air drawn
into the canister passes through only four components: the heated inlet line, a 2-micron particulate filter, the
electron flow controller, and the latching solenoid valve.
2. Summary of Method
2.1 In operation, timer 1 is set to start the pump about 6 hours before the scheduled sample period. The pump
draws sample air in through the sample inlet and particulate filter to purge and equilibrate these components, at
a flow rate limited by the capillary to approximately 100 mL/min. Timer 1 also energizes the heated inlet line
to allow it to come up to its controlled temperature of 65 to 70 degrees C, and turns on the flow controller to allow
it to stabilize. The pump draws additional sample air through the flow controller by way of the normally open
port of the 3-way solenoid valve. This flow purges the flow controller and allows it to achieve a stable controlled
flow at the specified sample flow rate prior to the sample period.
2.2 At the scheduled start of the sample period, timer 2 is set to activate both solenoid valves. When activated,
the 3-way solenoid valve closes its normally open port to stop the flow controller purge flow and opens its
normally closed port to start flow through the aldehyde sample cartridges. Simultaneously, the latching solenoid
valve opens to start sample flow through into the canister.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-81
-------
Method TO-14A
VOCs
2.3 At the end of the sample period, timer 2 closes the latching solenoid valve to stop the sample flow and seal
the sample in the canister and also de-energizes the pump, flow controller, 3-way solenoid, and heated inlet line.
During operation, the pump and sampler are located external to the sampler. The 2.4 meter (~8 foot) heated inlet
line is installed through the outside wall, with most of its length outside and terminated externally with an inverted
glass funnel to exclude precipitation. The indoor end is terminated in a stainless steel cross fitting to provide
connections for the canister sample and the two optional formaldehyde cartridge samples.
3. Sampler Installation
3.1 The sampler must be operated indoors with the temperature between 20-32°C (~68 to 90°F). The sampler
case should be located conveniently on a table, shelf, or other flat surface. Access to a source of 115 vac line
power (500 watts/min) is also required. The pump is removed from the sampler case and located remotely from
the sampler (connected with a 1/4 inch O.D. extension tubing and a suitable electrical extension cord).
3.2 Electrical Connections (-Figure C-l)
3.2.1 The sampler cover is removed. The sampler is not plugged into the 115 vac power until all other
electrical connections are completed.
3.2.2 The pump is plugged into its power connector (if not already connected) and the battery connectors are
snapped onto the battery packs on the covers of both timers.
3.2.3 The sampler power plug is inserted into a 115 volts ac line grounded receptacle. The sampler must be
grounded for operator safety. The electrical wires are routed and tied so they remain out of the way.
3.3 Pneumatic Connections
3.3.1 The length of 1/16 inch O.D. stainless steel tubing is connected from port A of the sampler (on the right
side of the flow controller module) to the air inlet line.
3.3.2 The pump is connected to the sampler with 1/4 inch O.D. plastic tubing. This tubing may be up to 7
meters (~20 feet) long. A short length of tubing is installed to reduce pump noise. All tubing is conveniently
routed and, if necessary, tied in place.
4. Sampler Preparation
4.1 Canister
4.1.1 The sample canister is installed no more than 2 days before the scheduled sampling day.
4.1.2 With timer #1 ON, the flow controller is allowed to warm up for at least 15 minutes, longer if possible.
4.1.3 An evacuated canister is connected to one of the short lengths of 1/8 inch O.D. stainless steel tubing
from port B (solenoid valve) of the sampler. The canister valve is left closed. The Swagelock® fitting on the
canister must not be cross-threaded. The connection is tightened snugly with a wrench.
4.1.4 The end of the other length of stainless steel tubing from port B (solenoid valve) is connected with a
Swagelock® plug.
4.1.5 If duplicate canisters are to be sampled, the plug is removed from the second 1/8 inch O.D. stainless
steel tubing from port B (solenoid valve) and the second canister is connected. The canister valve is left closed.
Page 14A-82
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
4.1.6 The ON button of timer #2 is pressed. The flow through the flow controller should be stopped by this
action.
4.1.7 The flow controller switch is turned to "READ" and the zero flow reading is obtained. If this reading
is not stable, wait until the reading is stabilized.
4.1.8 The flow controller switch is turned to "SET" and the flow setting is adjusted to the algebraic SUM
of the most recent entry on Table C-l and the zero reading obtained in step 4.1.7 (If the zero reading is negative,
SUBTRACT the zero reading from the Table C-l value). Be sure to use the correct Table C-l flow value for one
or two canisters, as appropriate.
[Note: If the analytical laboratory determines that the canister sample pressure is too low or too high, a new
flow setting or settings will be issued for the sampler. The new flow setting should be recorded in Table C-l
and used until superseded by new settings.]
4.1.9 Timer #2 is turned OFF to again start the flow through the flow controller. With the pump (timer #1)
ON and the sampling valve (timer #2) OFF, the flow controller is turned to "READ" and the flow is verified to
be the same as the flow setting made in Section 4.1.8. If not, the flow setting is rechecked in Section 4.1.8 and
the flow setting is readjusted if necessary.
4.1.10 The OFF button of timer #1 is pressed to stop the pump.
4.1.11 The canister valve(s) are fully opened.
4.2 Timers
4.2.1 Timer #2 is set to turn ON at the scheduled ON time for the sample period, and OFF at the scheduled
OFF time (see the subsequent section on setting the timers). Normal ON time: 12:00 AM on the scheduled
sampling day. Normal OFF time: 11:59 PM, on the scheduled sampling day. The OFF time is 11:59 PM instead
of 12:00 AM so that the day number for the OFF time is the same as the day number for the ON time. Be sure
to set the correct day number.
4.2.2 Timer #1 is set to turn ON six (6) hours before the beginning of the scheduled sample period and OFF
at the scheduled OFF time for the sample period (same OFF time as for timer #2). See the subsequent section
on setting the timers. Normal ON time: 06:00 PM on the day prior to the scheduled sampling day. Normal OFF
time: 11:59 PM on the scheduled sampling day.
[Note: The timers are wired so that the pump will be on whenever either timer is on. Thus the pump will run
if timer #2 is ON even if timer #1 is OFF.]
4.2.3 The elapsed time meter is set to 0.
4.3 Sampler Check
4.3.1 The following must be verified before leaving the sampling site:
(1) Canister(s) is (are) connected properly and the unused connection is capped if only one canister is
used.
(2) Canister valve(s) is (are) opened.
(3) Both timers are programmed correctly for the scheduled sample period.
(4) Both timers are set to "AUTO".
(5) Both timers are initially OFF.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-83
-------
Method TO-14A
VOCs
(6) Both timers are set to the correct current time of day and day number.
(7) Elapsed time meter is set to 0.
4.4 Sampler Recovery (Post Sampling)
4.4.1 The valve on the canister is closed.
4.4.2 The canister is disconnected from the sampler, the sample data sheet is completed, and the canister is
prepared for shipment to the analytical laboratory.
4.4.3 If two canisters were sampled, Section 2.4.2 is repeated for the other canisters.
5. Timer Setting
Since the timers are 7-day timers, the days of the week are numbered from 1 to 7. The assignment of day
numbers to days of the week is indicated on the timer keypad: 1 = Sunday, 2 = Monday, 3 = Tuesday, 4 =
Wednesday, 5 = Thursday, 6 = Friday, and 7 = Saturday. This programming is quite simple, but some timers may
malfunction or operate erratically if not programmed exactly right. To assure correct operation, the timers should
be reset and completely reprogrammed "from scratch" for each sample. The correct current time of day is re-
entered to reprogram the timer. Any program in the timer's memory is erased by resetting the timer (pressing the
reset button). The timer is set by the following:
(1) pressing the reset button,
(2) entering the correct day number and time of day,
(3) entering the ON and OFF times for the sample period, and
(4) verifying that the ON and OFF time settings are correct.
5.1 Timer Reset
The timer reset button is pressed, which is recessed in a small hole just above the LED (light emitting diode)
indicator light. A small object that will fit through the hole, such as a pencil, match, or pen is used to press the
timer. After reset, the timer display should show 1 10:001.
[Note: The timers may operate erratically when the batteries are discharged, which happens when the
sampler is unplugged or without power for several hours. When the sampler is again powered up, several
hours may be required to recharge the batteries. To avoid discharging the batteries, the battery pack should
be disconnected from the timer when the sampler is unplugged.]
5.2 Date and Time Entry
The selector switch is turned to SET and the number button corresponding to the day number is pressed. For
example, a "2" is pressed for Monday. The current time of day is entered. For example, if the time is 9:00 AM,
900 is pressed. AM or PM is pressed as applicable. Display should show 2 | '9:00 for 9:00 AM Monday.
[Note: ' indicates AM and, indicates PM.]
Page 14A-84
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
-------
VOCs
Method TO-14A
The CLOCK button is pressed. Display should show | - If an error is made, E EE:EE | is shown on
the display. The CLEAR button is pressed and the above steps are repeated. The selector switch is turned to
AUTO or MAN to verify correct time setting.
5.3 ON and OFF Entry
The selector switch is turned to SET. The ON and OFF program is entered in the following order: day, number,
time, AM or PM, ON or OFF. (Example: To turn ON at 12:00 AM on day 5 (Thursday); 5, 1200, AM, ON is
entered). (Example: To turn OFF at 11:59 PM on day 5 (Thursday); 5, 11:59, PM, OFF is entered.) If the
display indicates an error (| E | EE:EE |), the timer is reset. The selector switch is turned to AUTO.
5.4 ON and OFF Verification
5.4.1 The selector switch is turned to REVIEW. The number of the scheduled sample day is pressed. ON
is pressed. The display should show the time of the beginning of the sample period (for example, 5 '12:001).
[' indicates AM.] ON is pressed again. The display should show 51 1, indicating no other ON times are
programmed.
5.4.2 OFF is pressed. The display should show the time of the end of the sample period, (for example, 15
, 11:591). PM is indicated by the mark before the time. OFF is pressed again. The display should show 15
—:—|, indicating no other OFF times are programmed. The selector is switched to AUTO. If anything is
incorrect, the timer is reset and reprogrammed.
TABLE C-l. NET FLOW CONTROLLER SETTING
DATE 1 CANISTER 2 CANISTERS
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 14A-85
-------
Method TO-14A
VOCs
Heated Inlet Line
DNPH-Coated
Sep-PAK
Formaldehyde
Cartridges
Glass
Funnel
Toggle
Valve
Duplicate
Filter/Orifice Assembly
Primary
3-Way
Solenoid
Valve
Prog.
Timer
Vacuum
Relief
Vent
NC
Pump Activated
Prior to
Sample Period
to Purge
Inlet Lines
NO
Vacuum
Pump
Prog.
Timer
Capillary
pMAH
~ 100 m'- /min
Latching
Solenoid
Valve
I
Particulate
Filter
Flow
Controller
(3-5 mL /min)
Sample
Canister
Figure C-l. Example of EPA's UATMP air sampler.
Page 14A-86
Compendium of Methods for Toxic Organic Air Pollutants
January 1999
------- |